The CPSC estimates that between 2003 and 2007, there have been over eleven thousand injuries caused by structural failure or collapse of guardrails at outdoor decks.  It’s not tough to understand why – when people have parties in the summer, everyone hangs out on the deck.  Throw in a keg of Busch Light, a few (ahem) ‘people’ that make the rockin’ world go ’round, and a weak guardrail… boom.  Guardrail collapse.  Weak guardrails are one of the most common safety issues with decks.

The current requirement for new deck guardrails is that they withstand 200 lbs of pressure at any point along the top rail (Table R301.5).  Actually, this standard applies to all guardrails, both inside and outside the house, but decks are the place where it matters most.

My standard method for testing guardrails has always been to just push on them a little.  If they feel weak, I recommend having them reinforced or rebuilt.  Once a guardrail moves an inch or two without much pressure, I stop pushing; I don’t want to be the one to break it.  Home inspections are supposed to be visual, I know, I know… but I like to touch stuff.

I’ve never used any type of testing equipment, but I recently picked up a fancy-schmancy piece of highly specialized deck guardrail testing equipment to help get a better idea of what 200 lbs of pressure felt like.  Jealous much?

Ok, it’s just an $8 bathroom scale.  After some playing around, I’ve learned that 200 lbs is about the most pressure that I can personally apply to the top rail of a guardrail, just by standing on the ground.  In the photo below I’m applying about 150 lbs of pressure, and I’m straining to do it.

The weakest point in most guardrails is always going to be at the end, where it terminates next to the house.  All that typically supports the guardrail at this location is the 4×4 post, assuming posts were used to construct the guardrails.   In the photo above, I’m pushing on the guardrail at the end.   This guardrail actually performed fairly well – most guardrails won’t tolerate nearly that much pressure.

The surest way to construct a guardrail that will withstand 200 lbs pounds of pressure is to use metal brackets that are designed just for this purpose.   A couple manufacturers that make such brackets are DeckLok and Simpson Strong-Tie.   If special metal brackets aren’t going to be used, the support posts should be constructed with full size 4x4s (not notched at the bottom), attached with through-bolts, and extra blocking usually needs to be installed to help keep the guardrail secure.

In the photo below, the ovals show where extra blocking was added.  This blocking tremendously stiffens the joist that the guardrail is attached to, making it so the guardrail won’t budge even when a full 200 lbs of pressure is applied.

The bottom line is that weak guardrails are a safety hazard that should be corrected, especially on decks that are high above the ground.  For specific guardrail construction methods and rules, turn to page 15 of the  Prescriptive Residential Wood Deck Construction Guide.

May is Deck Safety Month – Related Post:

How to prevent your deck from collapsing: start by attaching it properly

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

May is National Deck Safety Month, so I’m going to start off this month by writing about the most common cause of deck collapses – improper attachment to a building.  Most decks are supported on one side by the building, and on the opposite side by the earth.  The photo below shows a deck collapse that happened here in Minnesota, and this is exactly how most decks collapse.  The cause of collapse is quite obvious – it wasn’t attached properly.

Is your deck properly attached to the building?  It’s not always possible to know for sure, but today I’ll discuss a few different ways of attaching a deck to a building.  The piece of wood that connects a deck to a building is called the ledger, or ledger board.  I’ll be using this term repeatedly.

Lag Screws

Traditionally, lag screws have been the most common method of attaching decks to buildings.  To properly attach a deck ledger using 1/2″ lag screws, 5/16″ holes need to be pre-drilled through the ledger and rim joist.  After that, a 1/2″ hole should be drilled through the ledger only.   For specific spacing and installation instructions, you can turn to page 12 of the Prescriptive Residential Wood Deck Construction Guide.   There’s no way of knowing if all of these steps were followed just by looking at a deck, but if lag screws are visible, you can feel a little better about the deck attachment to the building.

One problem that I occasionally find with lag screws is that they’re not attached to anything substantial behind the ledger.  When a home is constructed with floor trusses and there is no rim joist for the deck to attach to, it’s important to figure out what the screws are going in to.  In the photos below, the lag screws at this Eden Prairie townhouse were only attached to the fiberboard wall sheathing, which is basically worthless.  You wouldn’t want to put too many people on that deck.

Lag screws are fairly inexpensive, but they take special steps to install correctly.

Special Ledger Screws

Because of the tedious process involved in drilling several pilot holes in the wood to use lag screws, there are a few products available that are designed for the specific purpose of attaching a deck ledger to a building.  One such fastener is the FastenMaster LedgerLok®, which is pictured above.  Simpson Strong-Tie makes a similar fastener, called the Strong-Drive® SDS Screw.  These fasteners are designed to be installed without any pilot holes, and they already come with a washer attached to each head.

While these fasteners may cost a little more, they’re fast and easy to install, and they’re code approved to be used in place of 1/2″ lag screws.

Through-Bolts

Through-bolts can be used to attach a ledger to the house when the interior of the rim joist is accessible.  This is typically done using carriage bolts, pictured above.   When through-bolts are used, you’ll either see the head of the bolt or the end of the bolt at the ledger.  Lag bolts work in a similar manner.

All things being equal, a through bolt makes for the strongest connection per fastener.  Without all things being equal, there are certainly ways of installing through-bolts improperly.  In the examples below, taken at a townhouse in Edina, you can see the end of the bolt where a washer and nut were fastened.  The problem with this installation is that someone didn’t have long enough bolts, so they had to chisel out a bunch of holes in the ledger to sink the washers and nuts in to.

This is probably the least common method of deck attachment because it takes more time, and requires more running in and out of the building.

Nailed Ledgers

Nails are not an acceptable way of attaching a ledger to the building, because they can pull out.  I don’t have any statistics to quote, but this is probably the most common cause of deck collapses.  If you look at a deck ledger and all you can see are nails holding it in place, it should be addressed.  This is one of the most common deck problems that home inspectors find, and the repair is usually an easy fix.

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

There’s a show on HGTV called Holmes Inspection, which exposes problems with houses that were allegedly missed by other home inspectors.  Here’s the basic formula: John and Jane buy a house, have it inspected, no major problems.  Time passes, problems show up, Mike Holmes gets called in.  Mike inspects the house, agrees there’s a problem, tears everything open to show what was done wrong or could have been done better, and then says he’ll “make it right”.  In the end, the original home inspector gets blamed for missing defects with the house.

I’ve had countless clients ask me about the show, and I’ve heard a lot of discussion about the show from other home inspectors, so I finally took the time to watch an episode to see what all the talk was about.

Holmes Inspection makes for great TV.  I watched an episode titled Frigid Floor, wherein the homeowners complained about a cold floor at the addition of their house.  There were a couple of other miscellaneous issues, but the big one was the cold floor.  Mike Holmes doesn’t know exactly what the problem is, so he has his crew come in and cut out a huge section of the kitchen floor to get at the crawl space below.  There is no final diagnosis of what the problem is, but his crew spares no expense in making it right.

They tear out all of the cabinets, countertops, flooring, and subfloor to get at the crawl space.  They spend three days hand digging the crawl space to make it several feet deeper, install rigid foam on the floor, pour self-leveling concrete on the floor, then have the walls insulated with spray foam (I loved that part).  While they’re at it, they also beef up the floor structure.  They add access to the crawl space from inside the basement by cutting an opening through the foundation wall, and they add a heat register and a light.   They definitely ‘make it right’.

The original contractor who did the addition gets thrown under the bus; Mike says that this is how the job should have been done to start with.  While Mike’s work was far superior to that of the original contractor, I think it’s unfair to put down the original contractor.  The work was done for the previous owner, permits were pulled, and the work was inspected and approved.  We have no idea of what was agreed upon between the original contractor and the previous owners.  Maybe the original contractor gave the previous owners a bid to do exactly what Mike Holmes did, and the owners opted to save $10k by only doing the bare minimum.

If the previous owners got three different bids for the job, there’s a slim chance that the contractor who gave them a bid on a beautiful crawl space would actually get the job.

The original home inspector gets thrown under the bus as well.  Mike concludes the show by saying that if the original home inspector actually knew something about construction,  he would have warned the buyers that there was no crawl space.   That comment really bugged me.  The home did have a crawl space, it just didn’t have any access, and it was too small for most people to actually crawl in to; that doesn’t mean it’s not a crawl space.  I’d love to know what Mike would have said to the buyers if he had done the original home inspection.   Here are a few potential warnings:

• This home has no accessible crawl space.  So what?
• This home has no accessible crawl space, but it should.  I can’t inspect what I can’t see.  Before you buy this house, you should have the sellers make the crawl space accessible and have it inspected.  The home inspection was performed in warm weather, and there were no signs of any problems.  The work was done with permits and inspected, so what would actually happen if the buyers demanded the crawl space be made accessible for the inspection?  Do you think the sellers would agree to that?  My experience tells me absolutely not.
• This home has no accessible crawl space.  I know that permits were pulled for the addition and inspected by the city, but I don’t care.  If I can’t see it, it’s probably not right.  Don’t buy this house.  Ha!  Now I’m just being silly… I think.

Just for the sake of argument, let’s say the inspection was done during the winter, the floor was cold, and the crawl space was barely accessible.  What would the recommendation have been?  Gut the kitchen and make it right?  That suggestion would go over like a lead balloon.  Personally, I would have told the buyers that the floor was cold, and to fix it would probably be cost prohibitive.  This is what you’re getting, take it or leave it.

My conclusion

I’m not trying to be too critical of the show, but the repairs performed on this house were completely over-the-top and unrealistic.  Don’t get me wrong, it’s a very cool concept for a show – take a problem with a house that is cost prohibitive to repair and fix it any way you want with time and money being no object.   It would have been nice to do it this way from the start, sure… but I can’t imagine any sane person spending their own money gutting a kitchen just to make the floor warmer.  This is a fun show to watch as long as you remember that it’s just TV.  I think the main messages are good: hire an excellent home inspector and don’t skimp out on your remodel project.  You’ll save money in the long run by spending a little more up front.

I think I’ll start watching this show.

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

One of the most common defects I find with asphalt shingles is improper nailing.  The manufacturers of asphalt shingles give specific instructions on how to fasten shingles, and they’re all pretty much the same.  Unfortunately, following those instructions seems to be a difficult thing to do for a lot of roofers in Minnesota.  The two most common nailing defects that I find with shingles are overdriven nails and improperly located nails.

Overdriven Nails

Most roofers use pneumatic nail guns to nail down shingles.  When the pressure is set too high, the nails get driven in to the shingles too far, plain and simple.  When the nails are overdriven, the heads of the nails punch right through the mat of the shingle.  This voids the shingle manufacturers warranty and greatly increases the potential for shingles to come loose and blow off, possibly in sheets.

The diagram below shows what proper and improperly driven nails look like.

The photos below show several examples of overdriven nails.

Improperly Located Nails

The other most common nailing defect that I find with asphalt shingles is improperly located nails; specifically, high nails.  When shingles are located too low on a shingle, it’s an obvious defect that anyone with a good eye can usually spot from the ground.  This is probably why I don’t find this defect all that often; it’s just too obvious of a defect for most roofers to leave uncovered.

The more common and problematic nailing problem is to have nails located too high on the shingle.  There is a fairly narrow strip on every shingle where it’s acceptable to place the nail.  When properly placed, the nail will actually catch the top edge of the shingle below it.  When nails are located too high on the shingle, they never catch the shingle below, which effectively cuts the amount of nails going in to each shingle in half.  Hopefully my diagram below will help to illustrate this; the blue dots are supposed to be nail heads.

The photos below show examples of high nailing.  Yes, I know what I did there.

When shingles are improperly fastened, they have a tendency to slide and rip out of the nails holes, and this won’t be covered by the manufacturers warranty.  When the entire roof covering is installed like this, there is no simple fix.  Either the new buyers need to accept the fact that their roof will be prone to having shingles blow off, or the roof covering will need to be repaired or replaced.

These installation defects can’t be seen from the ground, even with a very expensive pair of binoculars.  For this reason, you shouldn’t expect most municipal inspectors to identify these issues; it’s outside the scope of their inspection.  I wrote about this topic here – Who Inspected Your Roof?  If you want a thorough roof inspection, you would do well to hire a home inspector who will access the roof.

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

I heard Adam Carolla mention this quick tip, and it really works.  I had to pass this along.  If you need to drill a hole in your wall and you don’t want to make a mess on the floor, just use a Post-it^® note.

3/8" hole in a 2x6

You make a couple of quick folds, paste the paper on the wall, then drill your hole.  All of the drywall dust or whatever you’re drilling in to will fall on to the paper.  Done and done.

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