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Reuben's Home Inspection Blog

Home Inspection topics in the Twin Cities area

By Reuben Saltzman | Home Inspector in Minneapolis, MN
  • Insulating your basement? Start with the rim space.

    Posted Under: Remodel & Renovate in Minneapolis, Going Green in Minneapolis  |  December 13, 2011 3:05 AM  |  1,722 views  |  2 comments

    Have you ever noticed how snow will melt around the foundation on older houses?  This will happen at any house with unheated foundation walls, and it's a great visual indication of how the house is losing heat.   When there's no melted snow up against the house, we can rely on thermal imaging to figure out where the heat loss is occurring.  In the image below it's right at the rim space; that's the part that shows up as the brightest orange / yellow.

    Heat loss at rim joist

    While houses usually act like chimneys, sucking air in at the bottom and exhausting air through leaks at the top, the photo below is a perfect example showing how it doesn't always work that way.  The frost that has accumulated against the siding is all coming from air that's leaking out of the un-insulated, un-sealed rim space.   It was about -15 degrees outside when I took the photo below.

    Frost on house

    To cut down on basement heat loss, an obvious place to start at is the rim space.  I mentioned this a couple weeks ago when I wrote my post about how I had my entire basement re-insulated, but today I'm going to focus on the rim space alone and discuss the different options for insulating and air sealing this space.

    Rim joist

    The old way of insulating rim joists was to use fiberglass batts.  As I've mentioned many times in previous blogs, fiberglass batts are a poor choice of insulation for any project... but they should never be used at the rim space because it's nearly  impossible to install a proper vapor barrier here, and fiberglass batts will allow for a lot of air leakage.   Without a vapor barrier at the rim space, you'll have relatively warm, moist air passing through the fiberglass insulation and then condensing at the rim joist.  This can create mold or rotting.

    There are only two ways that I ever recommend to insulate the rim space: rigid foam or spray foam.

    Using spray foam at the rim space is just about the only thing that is ever done on new construction houses in Minnesota today; while it's expensive, it's worth it because it can be applied quickly and does a perfect job of both insulating and air sealing the rim space.  Wires, faucets, pipes... they're no match for spray foam.  All of the penetrations get sealed.

    Spray Foam at Rim Space

    While spray foam is supposed to be covered by an approved material to prevent the possible spread of a fire, the rim space is one exception to this rule; this exception can be found in the Minnesota Amendments to the IRC, sectionR314.5.11.  Here in Minnesota, up to 5 1/2" of foam insulation can be sprayed at the rim space and left exposed.  The only downside to using foam insulation is that it's relatively expensive.  You can buy do-it-yourself insulation kits for fairly small jobs, such as a rim space, but I would personally just hire a professional to do this.  It wouldn't cost much more than a spray foam insulation kit.

    The alternative to having spray foam applied at the rim space is to install rigid foam insulation.  Installing foam insulation at the rim space takes a long time, but it's not a very difficult project.  Basically, pieces of rigid foam boards get cut to size, placed at the rim space, and caulked or foamed in place to help prevent air leakage.

    Rigid Foam at Rim Space

    While writing this post, I came across a great blog written by a handy homeowner, showing how he insulated his own rim space with rigid foam.  You can view it here - rigid foam at rim space.

    The one thing to remember when making a house tighter is that you'll have less air leaking in to and out of your house, which can create other problems, such as a backdrafting water heater or excessive moisture in the home.  The Minnesota Department of Commerce Energy Information Center has a great handout that specifically addresses this topic, which you can download here - Combustion & Makeup Air.

    If you don't have any insulation at your rim space, add this project to your list of 'to-do' projects.  It's not as critical as attic insulation and it takes more time, but it's a good thing to do.  Just don't use fiberglass.

    Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspector

            

  • I'm thankful for closed-cell foam insulation. Yeah, that's right.

    Posted Under: Remodel & Renovate in Maple Grove, Going Green in Maple Grove, Property Q&A in Maple Grove  |  November 22, 2011 3:07 AM  |  2,542 views  |  2 comments

    Yes, you read that right.  I'm thankful for closed cell foam insulation.  Of course, I'm thankful for my family, health, and all that other jazz, but this is a blog about home inspections and home related topics, so I'm going to stay focused on that.  To fully explain why I'm so thankful for closed cell foam insulation, I first need to complain about my house a little bit.

    My thirteen-year-old Maple Grove house has an unfinished basement with a walkout; this means about half of the basement walls have a poured concrete foundation, and the other half, the part that's above grade, has conventional 2x6 wood framing.  The foundation walls are insulated at the exterior with rigid foam; this is a great way to insulate a foundation, because it means that the concrete walls will be relatively warm, and the potential for condensation problems will be minimized.  If you want to read more about foundation insulation methods, click this link - foundation insulation.

    Fiberglass insulationThe stud walls, on the other hand, were insulated the same way as 99.9% of the houses in Minnesota - with fiberglass batts.  Yuck.  While this is the standard way to insulate a wall, it's also probably the worst acceptable way to insulate a wall.  The photo at right gives a great example of how fiberglass batts are installed incorrectly all the time; just look at those gaps around the junction box.  I've already dedicated a blog to complaining about fiberglass batts, so enough on that topic.

    In addition to having fiberglass batts for insulation, the vapor barrier in my basement was basically useless.  Here's how a vapor barrier is supposed to work: to prevent air from passing through the fiberglass insulation and creating moisture problems in the wall, a vapor barrier gets installed.  This consists of 6 mil polyethylene sheeting (aka 'poly', aka 'Visqueen') that has been made airtight; that means caulked, overlapped, sealed, taped, etc.  On a home built today, this will be done quite well.  On a house that's thirteen years old... no way.  The vapor barrier will probably be just about useless.

    Unsealed vapor barriers create heat loss.  Just thirteen years ago, vapor barrier were never sealed. It was standard practice to just use a stapler to throw the poly on the walls and leave everything completely unsealed.  This practice allows for air to constantly circulate within the fiberglass insulation, creating a convective loop, which means a lot of heat gets lost through the walls.

    I have my 'office' set up in my unfinished basement, so I spend a lot of time in the basement.  During the winter it gets very cold in my basement, despite the fact that I have 2x6 walls filled with fiberglass insulation.  Last winter I kept an electric space heater under my desk to keep my toes from turning in to icicles.

    rim joist insulationFiberglass should never be used at rim spaces.  The rim space is the area between the floors of a house; this is an area where it's nearly impossible to install a proper vapor barrier.  Without a vapor barrier, condensation can occur at the rim space, creating mold growth or eventually rotting out the rim space.  This is why fiberglass insulation should never be used here.  On new homes, it never is.  The only type of insulation that gets used on new construction homes in Minnesota is closed cell spray foam insulation; we'll come back to that in a minute.

    Unsealed vapor barriers can lead to mold growth.  When a vapor barrier isn't sealed and air is allowed to freely pass through the wall, what happens when warm, moist air hits a cold surface?  It condenses.  My basement stays relatively cool and dry throughout the year, so the vapor drive is really happening from the exterior during the summer.  The walkout part of my basement faces south, so this part of the house is where I have the greatest temperature differential between the exterior and interior of the walls.

    During the summer, as humid outdoor air passes through my walls and hits the relatively cool vapor barrier, the moisture condenses.  This summer there was never enough moisture to actually drip down to the floor, but it was enough to leave drip marks in the insulation and allow mold to start growing between the insulation and the vapor barrier.  This wasn't major and I don't have mold allergies, so I wasn't too whipped up about this... but I couldn't allow this to continue.

    Mold in fiberglass batts Mold in fiberglass batts 2

    Enter closed-cell spray foam insulation.  To address all of the insulation, mold, and vapor barrier issues at the same time, I had the wood framed walls in my basement completely re-insulated about three weeks ago.  I had the vapor barriers removed, all of the fiberglass insulation removed, and closed cell foam sprayed in to the walls and rim spaces.

    Foamed walls

    I love it.  Closed cell foam acts as a perfect vapor barrier after 2", it doesn't allow for convection, and it has a much higher insulating value than fiberglass.  Now when I walk down to my basement, I don't feel a drastic change in temperature; my basement is only about two degrees cooler than the rest of my house.  I can sit here at the computer without a space heater, and I no longer freeze my toes off.  Life is good.

    Having foam insulation sprayed in to the walls was expensive, but it was worth every penny.  Will I ever get a payback in energy savings?  I'm not sure.  I didn't even bother to check the numbers, because my main motivation for this project was comfort.  Saving energy and not having mold growing inside the wall cavities is just a bonus.

    Happy Thanksgiving.

    Reuben Saltzman, Structure Tech Home Inspections - Email- Maple Grove Home Inspector

            

  • Tankless Water Heaters Revisited

    Posted Under: Remodel & Renovate in Minneapolis, Going Green in Minneapolis  |  October 25, 2011 3:02 AM  |  1,886 views  |  No comments

    In last week's blog post, I discussed the amount of money I might save by having a tankless water heater installed, and I concluded that I would never see a return on my investment.  I received a lot of good feedback from that post, both for and against tankless water heaters.  I thought it would be worth bringing up a few few of these points in another post.

    Pros

    • You can't put a price tag on going green.  There's no dispute about this - tankless water heaters use less energy.  Doing the environmentally responsible thing doesn't always have a measurable return on investment.  I mentioned this last week, but only briefly.   Not everything we spend money on will give us a return on our investment - we all know that.   After all, what's the payback period on a sofa?
    • Tankless water heaters make sense for a cabin / vacation home.  Traditional water heaters have a 'vacation' setting, but I've heard it's a bad idea to use this setting, because it greatly increases the potential for legionella pneumophila growth.   Having a tankless water heater installed in one of these settings would result in much more than a 25% fuel savings.
    • Energy Star Tax Credit.  This $300 tax credit which includes tankless water heaters, expires December 31, 2011.   You can read about it here - tax credit.  I'm guessing we'll see another one show up when this one ends.
    • Fuel costs will continue to rise.  As we all know, fuel costs continually increase.  If fuel costs tripled in the next 20 years at a linear rate, a tankless water heater would actually give me a return on my investment, using the numbers from the example last week.

    Cons

    • Low water flow = no hot water.  If there isn't enough hot water flow, a tankless water heater just won't turn on.  One person even commented that they had to turn on the hot water faucet at their bathroom sink and leave it on the entire time they took a shower, or they couldn't get hot water.  For instance, Rinnai tankless water heaters needat least .6 gallons per minute, Bosch needs .65 gallons per minute, and Rheem at least .4 gallons per minute of hot water flow to kick on.
    • The cold water sandwich.  If you think gefilte fish sandwiches sound bad, just try one of these.  The cold water sandwich effect is something that happens with every tankless water heater.  When the faucet is turned on, off, and on again, you'll end up with a slug of cold water interrupting your hot water flow.  Some tankless water heaters require the call for hot water to last for at least three seconds before the burners turn on, so there can be several layers of hot and cold water in the pipes.  This doesn't exist with traditional water heaters.  You can read more about this at Rinnai's web site - they claim to have nearly eliminated the cold water sandwich, but not completely.
    • The long wait for hot water.  I already have to wait for approximately forever to get hot water at my kitchen sink, but the wait would be even longer with a tankless water heater.  One interesting solution that I heard a plumber mention was to install a dedicated 3/8" supply line to his kitchen sink from the water heater.   He claimed that this still provided just as much water flow, and made the wait much shorter.  I've considered doing this at my own house, although this is technically a code violation.

    For me, a tankless water heater doesn't make sense just yet.  I'm waiting for the price gap between tankless water heaters and standard water heaters to get a little smaller.  I have the temperature cranked up on my water heater with atempering valve installed, so I never run out of hot water.  Maybe by the time my kids are teenagers I'll have a different opinion of tankless water heaters.

    Reuben Saltzman, Structure Tech Home Inspections - Email - Home Inspector Minneapolis

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  • My Beef With Tankless Water Heaters

    Posted Under: Remodel & Renovate in Minneapolis, Going Green in Minneapolis  |  October 18, 2011 3:14 AM  |  2,020 views  |  No comments

    Reuben's BeefTankless water heaters are sexy.  They take up less floor space, they provide an endless flow of hot water, they're environmentally conscious... and they're really expensive.   If you enjoy showing off your home's mechanical equipment to your friends or you're in to being green at any cost, get a tankless water heater. On the other hand, if you're in to saving dough, doughn't buy a tankless water heater.

    A tankless water heater will not save you money.

    I stopped by my local big orange box the other day to check up on the latest sales pitch for tankless water heaters.  The brochure for tankless water heaters said they can save up to 25% in fuel costs.  That sounds great, but lets examine what that means. I spend about $12 per month for natural gas during the non-heating season, if I don't include my fixed fuel costs, such as the 'fuel delivery charge.'  This figure includes the gas for my water heater, clothes dryer, and oven.  Just for the sake of argument, lets also pretend that I don't have a family of four who uses the clothes dryer all the time, and I don't use the oven all the time.  We'll pretend that I spend the full $12 / month just  to keep a 50 gallon tank of water hot all the time.

    Fuel savings

    If I save 25%, I'll save $3/month, or $36/year, or $720 over a period of 20 years.  My standard 50 gallon water heater has a 12 year warranty, and so does the tankless water heater I looked at... but the life expectancy for a tankless water heater is apparently 20 years, so I'll give it the benefit of the doubt and assume it will last that long.

    Sizing a tankless water heater

    The brochure on tankless water heaters said I should buy the largest tankless water heater they make, based on the number of bathrooms I have in my house - three.   The particular model is the ECOH200DVN.  This unit boasts a 9.5 gallon per minute flow rate at a 35 degree rise in temperature.  With an average ground water temperature of 45 degrees here in Minnesota, that would give me... 80 degree water.  Ha!  That's useless.  To get 120 degree water, my flow rate would be reduced to 5.1 gallons per minute.  Maybe I'll need two water heaters. For the sake of argument, lets just say I only need one.  This unit retails at my local Home Depot for $1,427.00.

    Installation costs

    Plumbers charge a lot more money to install tankless water heaters, because they're a lot more work compared to traditional storage tank water heaters.  The water supply pipes will need to be re-routed, the venting will need to be completely redone, the unit will need to be mounted on a wall, an electrical outlet may need to be added, and the gas pipe may need to be re-done.  Just for fun, let's say you were able to find a plumber to do all of this for $1,000.   A traditional water heater might cost up to $500 in labor for replacement, so we'll assume you're only spending an extra $500 in labor for a tankless water heater.

    The bottom line

    A traditional 50 gallon water heater with a 12 year warranty retails for $559 at my local Home Depot.   I would spend an extra $868 to buy a tankless water heater, and at least an extra $500 in installation costs, making this unit cost at least $1,368 more than a traditional water heater.  I would spend at least $1,368 for the potential of saving $720 over a period of 20 years.  If I ever buy a tankless water heater, I won't be doing it because I'm hoping to save money.

    Related links:

    Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspector

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  • Conducting Your Own Deck Inspections

    Posted Under: Home Buying in Maple Grove, Remodel & Renovate in Maple Grove, Property Q&A in Maple Grove  |  May 3, 2011 3:18 AM  |  1,774 views  |  No comments

    As I'm sure you already know, May is Deck Safety Month, so it's a good time to talk about deck inspections.  Is your own deck safe?  Now is the time to check.  If you're going to have a party or a large gathering, you better be sure.  The best way to be sure is to pack as many people on to your deck at one time as you possibly can, and have them bounce up and down all at once.  If your deck doesn't collapse, it's safe.

    Collapsed Deck
    Ok, that's a joke.  Seriously, the best way to know about your deck is to have it professionally inspected. As I've said before, building a deck and replacing a water heater are two of the most common projects that get royally screwed up by DIYers on a regular basis.  If you're not keen on hiring a home inspector or carpenter to check out your deck, there are still a few basic things that you can look for yourself.

    Improper attachment to the house

    The most common reason for deck collapses is improper attachment at the house.  That's what happened with the deck pictured above.  If the deck is supported by the house, it should be attached with bolts, lag screws, SDS screws, or some other similar method.  The photo below shows proper attachment with lag screws, which I've circled in black.  This is the most common deck ledgerboard attachment method.  If you look at the deck attachment to your house and all you see are nails or small screws, you have a problem.

    Lag Screws

    Improper flashing at the house

    There should always be flashing installed above the top of the ledgerboard - that piece of wood that attaches the deck to the house.  The purpose of the flashing is to keep water from leaking in behind the deck at the house and causing rot.  Here in Minnesota, painted galvanized steel is pretty much the standard way to flash the ledgerboard.

    To determine if the ledgerboard is flashed, just take a peek underneath the deck.  If you can see a piece of metal sticking out over the edge of the ledgerboard from underneath, you know that flashing is present.  This doesn't mean it was installed properly, but you should at least feel a little bit better knowing it's there. If installed properly, this flashing will extend up underneath the siding.  The photo below shows what you should see if the flashing is properly installed; I drew a black rectangle around it.

    Ledgerboard flashing

    If there is no flashing present, there will be a much higher chance for water instrusion and rotting.

    Improper joist hanger installation

    Joist HangerJoist hangers are those metal brackets that attach the deck joists to the house and beams.  The manufacturers of joist hangers are very specific about how joist hangers should be installed; they specify exactly which nails should be installed, and exactly how much weight the joist hangers will support when installed properly.   Here are a few defects that I regularly find with joist hangers:

    • Missing nails.  Nails are supposed to be installed in every hole.
    • Improper joist hanger nails.  I find improper joist hanger nails on almost every deck.  If you can see a little "10" on the head of the nail, it's probably the wrong nail.  Click the link above for more details on this defect.
    • Screws used instead of nails.  Screws don't have nearly the shear strength of nails, and they're not an acceptable substitute.  Well, there's one screw I know of that's an acceptable substitute, but I've never actually see it installed.  Joist hanger screw
    • Altered joist hangers.  Joist hangers shouldn't be bent or cut.

    Rot

    Get a screwdriver and poke around your deck looking for rot.  The area that usually rots first is the place where two deck boards butt up against each other over a joist.  Pay special attention to that location.  If your deck doesn't have the aforementioned ledgerboard flashing, you should also pay special attention to the place where the deck connects to the house.  This video shows me inspecting a rotted deck in Minnesota last year.

    Improper stairway attachment

    The best way to attach a stairway stringer to a deck is to use a metal bracket that's designed just for this purpose.  The photo below left shows a proper bracket for a stairway stringer.  This bracket isn't the only way to properly attach a stairway stringer, but it's probably the best way.  The photo below right shows an improper installation; they used a joist hanger bracket, and only managed to get a couple nails in the entire bracket.  Not cool, and not uncommon.

    Stairway Stringer Bracket Improper stairway stringer attachment

    Guardrail problems

    Guardrails should be strong.  If you can push on the top of your guardrail and it moves a couple inches, it's not strong enough; guardrails should be able to withstand 200 lbs of pressure along the top rail in any direction.  While this may seem like a lot, just think about a group of people leaning against a guardrail while heavyset guy who's had three too many mint juleps falls against the guardrail.  If a guardrail is supported only with 2x2 balusters, it's probably way too weak and should be reinforced.  You can read more about this topic at my blog about guardrail requirements.

    Also, the current requirement for guardrails is that the balusters be spaced so that a 4" sphere can't pass through.  This is a requirement so little kids don't get their heads stuck.  Common sense also tells you that you don't want horizontal balusters that little kids can climb like a ladder, but there's nothing in the building code that prohibits this design.

    That makes up my list of the most common deck defects that you can look for yourself.  This isn't a comprehensive list, but it's a great starting point.  If you'd like a comprehensive but much less user-friendly list of things to look for while conducting your own deck inspection, you can download a deck inspection checklist from the North American Deck and Railing Association.

    Reuben Saltzman, Structure Tech Home Inspections - Email- Minnesota Deck Inspections

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  • The Best Way To Insulate An Attic

    Posted Under: Remodel & Renovate in Edina, Going Green in Edina  |  March 29, 2011 3:06 AM  |  1,797 views  |  4 comments

    Unfortunately, the easiest way to add insulation to just about any place in your home is to install fiberglass batts.  Fiberglass batts are typically the worst insulation for any job, as I complained about in a recent blog.  I mentioned at that time that I would follow up with a blog about the other choices of insulation.  Today I'm going to discuss several different types of attic insulation.

    The best way to insulate an attic or pretty much anything else in a home is to use spray foam insulation. There are two types of spray foam insulation; open cell and closed cell. I've also heard people call them 'half pound' and 'two pound' foams, respectively.  Open cell foam has an insulation value of up to R-3.9 / inch, while closed cell has an insulation value of up to R-6.9 / inch.  Closed cell foam will act as a vapor barrier when installed to a depth of at least 2", while open cell foam won't act like a vapor barrier at any depth.  For an in-depth discussion of the differences between closed cell and open cell foam, click here open cell vs closed cell foam.

    When properly installed, either type of spray foam insulation will act as a perfect air barrier, sealing off all attic bypasses.  Spray foam insulation will also completely eliminate convection; air cannot move through foam insulation.   The downside to using foam insulation is the expense; foam costs way more money than anything else, and it's definitely not a do-it-yourself product.

    I've heard some people complain about the flammability of foam insulation; yes, it's flammable, but it will typically be completely covered in the attic.  The fact that it's flammable wouldn't stop me from installing it.  If you're curious, here's a quick "don't try this at home" video.

    I'm such a firm believer in spray foam insulation that I had this done at my previous home, which was a one-and-one-half-story house.  For this style of house, foam is definitely the way to go; the insulation gets applied directly to the roof decking, and it's called a hot roof.  The foam gets completely covered with drywall after that.  For traditional roofs, I've made up my own set of standards.

    The Gold Standard

    For a traditional attic, there is no need to use foam throughout the entire space, as you'll get the most value out of the first couple inches.  A cost effective way to use foam insulation is to foam the lid of the house, then use loose fill insulation on top.  This means installing spray foam to a depth of at least 2" on the entire attic floor to completely seal everything up.  After the foam is cured, loose fill fiberglass or cellulose insulation gets installed on top of the foam.  Because fiberglass costs more, has a lower insulation value per inch and makes my skin itch, my preference would be cellulose.

    If it's an older home with only a few inches of space between the tops of the outer walls and the roof, you won't have much room for insulation here; extra spray foam needs to be installed here to help compensate for this.

    Here in Minnesota, the minimum allowable insulation value for a new construction home is R-38 for an attic, but federal standards suggest R-50 for our climate.

    Oh, and one other cool thing about spraying closed cell foam on the attic floor is that once the foam cures, you'll be able to walk on the entire attic floor; not just the truss or floor joists.  I've done it.  It's crazy.  That closed cell foam is strong stuff.

    The Silver Standard

    Prep the attic before insulation.  Have every attic bypass completely sealed.  Foam in a can is great stuff for mostsmaller attic bypasses (didja see what I did there?), but watch out for gas vents; they require a 1" clearance.  Have insulated boxes constructed for any recessed lights - they contribute a ton of heat to the attic.  If it's an older home where the rafters or trusses only leave a few inches for insulation at the outer walls, you won't have enough room for proper insulation at the edges; hire someone to spray foam these areas with closed cell foam to get the highest insulation value possible.  Of course, don't forget to install baffles at the eaves to prevent your soffit vents from getting blocked.

    After everything has been prepped, it's time to insulate.  My preference is cellulose insulation.  If you do it yourself, you can buy the insulation in bags from your local home improvement store, and they'll probably let you rent an insulation blower for free.  The DIY cellulose insulation method is very dusty, but it'll get the job done.  If you hire a pro, they'll use wet-spray cellulose, which adds a small amount of water to the cellulose to help control the dust and to slightly increase the insulation value per inch.

    If you choose to use loose fill fiberglass instead, don't worry; it's not bad stuff.  There was a widely publicized study conducted by Oak Ridge Laboratories in 1991 that said that loose fill fiberglass insulation lost a lot of its insulation value once temperatures dropped below 20 degrees, making loose fill fiberglass an inferior product when compared to cellulose.  I contacted Andre Omer Desjarlais at Oak Ridge Laboratories about this issue, and he said "This was true 20 years ago but all fiberglass manufacturers have changed their products appreciably since then and this is simply no longer an issue."  I also contacted several insulation manufacturers about this, and they said the same thing and sent me some great information, which I posted on my web site; click any of these links to read the documents from Certainteed, Johns Manville, or Owens Corning.  Loose fill insulation will still experience convection, but not nearly as much as old fiberglass used to.

    The Bronze Standard

    Just use cellulose insulation in the attic.  Cellulose does a good job of controlling condensation in the attic and it's a fairly dense product, so it will cut down on air movement from attic bypasses, but won't completely eliminate them.

    The Brown Standard

    Roll out a bunch of fiberglass batts, proudly proclaim "done and done", and have yourself a cold one.

    Oh, and as for the attic access panels or pulldown attic steps?  I'll cover those in another blog.

    Reuben Saltzman, Structure Tech Home Inspections - Email - Edina Home Inspections

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  • Thinking of adding more insulation to your attic? Read this first.

    Posted Under: Remodel & Renovate in Maple Grove, Going Green in Maple Grove, Property Q&A in Maple Grove  |  February 15, 2011 3:01 AM  |  1,469 views  |  6 comments

    If you're tired of dealing with ice dams and you've decided to finally get your attic re-insulated, please read this first.  You might save yourself a lot of time and money.

    Over the past two months, a large portion of my business has been ice dam inspections in Minnesota.   For most of these inspections, I was hired to determine the cause of the ice dams and to recommend a solution.

    I feel extremely fortunate to have spent the past two months doing this.  During this time, I've dug through a ridiculous amount of insulation in attics.   I've come home with itching arms, neck, cheeks, and red eyes (I'm pretty sure fiberglass insulation was invented by a very evil person).  Most importantly, I've learned quite a bit about attics.

    I'd like to share the complaints I've heard from homeowners, what I've learned, and what I've recommended.  My goal is to help homeowners benefit from my experience.

    What I've Heard

    I had more insulation added to my attic after last winter, but the ice dams are just as bad as they were last year, if not worse!

    I heard versions of this statement over and over from frustrated homeowners.  Just adding more insulation typically won't fix ice dam problems.  I'll come back to this.

    I just had a new roof installed, and the roofer said they laid down a rubber membrane going six feet up.  Obviously my roofer is a liar, because if they really had laid down a rubber membrane like they said, my roof wouldn't be leaking.

    I've heard so many versions of this!  The 'rubber membrane' that everyone refers to is actually an underlayment that's commonly referred to as an ice and water shield.  This underlayment is required by the Minnesota State Building Code; it must be installed underneath the shingles and "extend from the eave's edge to a point at least 24 inches inside the exterior wall line of the building."  This stuff comes in a three foot roll, and roofers usually have to lay down two layers of it to get 24" inside the exterior wall line, so it's usually six feet.

    Ice and water shield will not prevent roof leakage from ice dams. Ice dams can cause leaks above the underlayment, or even right through the underlayment; I've seen it happen.  According to Certainteed, the manufacturer of Winterguard underlayment, it "provides your first line of defense."  It's not a guarantee against leaks.

    If you have ice dams and your roof leaks during the winter, don't blame your roofer.  I can almost guarantee you that it has nothing to do with the way your roof was installed.

    Why do I live in Minnesota?

    This last weekend was a great reminder of why we live in Minnesota.  The temperature shoots up to 40 degrees and it feels like summer is around the corner.

    What I've Learned

    Gutters don't cause ice dams. Ok, I always knew this, but I've noticed plenty of ice dams with no gutters this year.  Ice dams will show up whether gutters are installed or not.  I mention this because I actually heard a 'professional' guest on a local radio show say that gutters cause ice dams, and that homes without gutters won't get ice dams.  I'm sorry, but that just ain't true.  You should have seen me 'calmly' disagreeing with my radio when I heard this.

    Ice dam with no gutters 3

    Ventilation has little to do with ice dams. I'm sure I'll get plenty of indignant feedback for this blasphemous statement.  I've always been taught that you won't get ice dams if you have enough ventilation, and I even used to preach this myself.  This is a concept that is deeply ingrained in the minds of contractors, roofers, and home inspectors everywhere.

    Nevertheless, from all of the houses I've been to, I've seen little to no relationship between attic ventilation and ice dams.  Sure, attic ventilation is required.  Attic ventilation will help to cool the attic space, which helps to cool the roof decking, which helps to prevent snow melt, which helps to prevent ice dams... but this is a very small part of the equation.

    The Minnesota Department of Commerce lists attic ventilation as a non-solution to ice dams.  The University of Minnesota Extension says that "only small amounts of roof ventilation are needed to maintain uniform roof surface temperatures."

    Adding more ventilation probably won't change your ice dam problems.  Shoveling the snow off your roof vents probably won't change your ice dam problems.

    Adding more insulation to your attic probably won't fix your ice dam problems. As I mentioned at the beginning of this blog, I've been to a ridiculous number of houses this winter where insulation was added, but the problems didn't go away.

    If an attic lacks insulation, it's probably an older attic.  Not always, but usually.  If it's an older attic, it's pretty much a guarantee that there are attic bypasses present.  Attic bypasses are passageways for warm air to get in to the attic, and they're the driving force behind ice dams.  In almost every home that I inspected this winter, attic bypasses were at the root of the ice dams, regardless of how much insulation was present.  Through the use of an infrared camera, I've learned that insulation can't make up for air leakage.

    It doesn't matter how much insulation is present in an attic; if there are air leaks, warm air will pass through traditional insulation.  The images below help to illustrate this; this was a very small attic bypass, but it still shows up plain as day through 14" of loose fill fiberglass and another 4" of cellulose on top of that.  I have hundreds of image sequences just like this.

    Attic bypass

    Recessed lights are huge contributors to ice dams. I recently wrote about this in another blog - Recessed Lights Are Evil.

    What I've Recommended

    I've recommended the same thing over and over; seal the attic bypasses.  They're the main cause of the ice dams.  When insulation has already been added to an attic space, this becomes an extremely difficult, if not impossible chore.  To access and seal the attic bypasses, you first need to know where they are.  When they're buried under one to two feet of insulation... forget it.

    An experienced insulation contractor might be good enough at their job to know where to look for most of the attic bypasses, and could spend their time digging through the insulation to find most of them, but without completely removing the existing insulation, there is no way to seal all of them.

    In most cases, I've told homeowners that they can hire an experienced insulation contractor to seal up all of the attic bypasses that they can find, and to keep their fingers crossed.  This will probably be enough to prevent leakage from ice dams again, and it will be a good repair, but not complete.  For a complete repair, all of the existing insulation needs to be removed so all of the attic bypasses can be located and sealed.

    If you're going to have insulation added to your attic, be sure to seal the attic bypasses first.

    Reuben Saltzman, Structure Tech Home Inspections - Email - Maple Grove Home Inspections

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