Structural Archives - Charles Buell Consulting LLC

November 21, 2017 by Charles Buell

Two wrongs still don’t make it right.

As you can see in the picture, the cut truss (wrong #1) is pointing right at the whole house fan (wrong #2).

While whole house fans may have been a good idea, once upon a time in some climates, they have virtually no place in modern energy efficient construction. In northern climates they are of particular concern as they are typically NOT adequately insulated and sealed against heat loss in the winter. When they are not insulated and sealed, the natural stack-effect of the home will pull warm air into the attic more or less around the clock.

The idea of these units is to flush the warm daytime air from the home at night, and then pull in the cool night air to cool the home off. Not a bad idea really. While this principle works in older poorly insulated homes, in modern well insulated homes they should not be necessary. Merely opening a few windows on opposite sides’ f the home should achieve the same result.

If the home is overheating during the day, one should look to the causes of that overheating and fixing the overheating as opposed to installing a system that should not be necessary. If one’s home is overheating and one considers it “well insulated,” I would argue that one should perhaps re-think one’s definition of “well insulated” or that perhaps there are other factors contributing to the overheating. A good question to ask might be, “what are the air sealing abilities of the insulation?” Not all insulation is created equal.

As a side note, I can pretty easily argue that even newly constructed homes in areas of the country with high cooling needs are NOT adequately insulated to appreciably reduce energy costs. Code requirements for energy conservation are “minimum” standards, and make no distinction between the air sealing characteristics of the various kinds of insulation.

If installed properly, and if used properly, and if maintained properly in the off season, these fans can help reduce air conditioning costs, improve comfort and improve air quality. Please note that this statement includes a lot of “ifs” and their installation can more often result in increased heating costs in the off season.

Another issue that arises from these fans is that if they are not sized properly (and they rarely are) they are capable of drawing more air into the attic than the attic space can get rid of. This can result in pressurizing the attic and minimizing the effectiveness of the fan—oversized or not. Regardless, even if additional venting is installed to compensate, there will then be compromised and possibly inadequate venting of the roof structure for that part of the year when the fan is merely wasting energy. It might be possible to balance these differences, but the reality is that often the different requirements for the different functions are simply not taken into account—or, worse yet, not even possible to take into account. More often than not, when I see them installed in the Northwest, they seem to be installed on the insistence of someone that has moved here from a climate where they worked or were possibly even necessary.

For the installation above, someone is now going to have to incur the cost of removing the fan and repairing the damaged truss. These costs will now need to be added to the increased energy costs created by the installation in the first place

By Charles Buell, Real Estate Inspections in Seattle

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December 23, 2016 by Charles Buell

Honey, the deck ate the WHOLE yard!

Honey?

Can we make the deck bigger?

In fact, can we cover the whole yard with it?

Sure honey—will get right on that this weekend!

What started out as a nice little rectangular deck on the back of the home, turned into a complicated series of decks, which did in fact cover much of the back yard. Decks can be maintenance nightmares and, as nice as they might be, it is important that they be constructed properly.

They must be supported properly, attached to the house properly and have safe guard railings. It is actually pretty unusual to find a deck that does not have one or more issues with it. Missing flashings at the ledger on the house, the ledger attached over the top of the siding, missing ledger bolting and/or missing joist hangers on the ledger are just a handful of the common issues found with just this part of the deck.

This is not intended to be a treatise on deck construction and my focus today is merely on how these newer decks were “connected” to the existing deck. There was no access under the deck so the picture I have of the underside had to rely on the light of my flashlight with the camera looking through the lattice that skirted the deck.

As you can see, the older original deck is all of the greenish/grey colored wood to the right in the picture. The newer deck is all the reddish/brown structures to the left in the picture. The board that divides the two is the original outer rim joist of the old deck. Notice that (as would have been common with attachment of the original rim joist) the board is merely nailed into the end grain of the joists. The joists are cantilevering across the top of the original beam that can be seen to the right side of the picture.

The new deck ledgers have been butted into the old rim joist and metal joist hangers have been used to support the joists at the attachment. So now we have half the weight of all the new deck structures that hangs on this rim joist being supported by the few nails driven into the end grain of the original cantilevered joists. This weight of course does not include whatever numbers of people are able to gather on the new portion of the deck. In this next picture—everything to the right of the red line in the picture is added to that original rim joist.

This deck has been this way for about 10 years so all is good right?

Depending on lots of factors, this connection may or may not fail catastrophically. I know my E & O policy would not be happy if it did. The size of the nails driven into the end grain is critical. Whether they can rust and corrode is critical. The total number of nails is critical. None of these can be actually determined in the course of a Standard Home Inspection.

The bottom line is that this type of connection would never stand up to modern deck construction “best practices” and the connection should be properly supported. It will likely be necessary to move the existing beam over under this connection or to add another one. Simply adding hangers on the other side may be sufficient but that would have to be determined by someone working beyond the scope of a Standard Home Inspection.

Sometimes the things that can be done on weekends should be left to weekdays.

By Charles Buell, Real Estate Inspections in Seattle

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October 24, 2016 by Charles Buell

You need to understand what you are working with.

This is a house I designed and built in 1978. For the most part it looks the way I built it, except for the big wrap-around deck and the addition to the back of the home.

On a recent adventure to see how some of my wood foundation houses are behaving (after more than 35 years), I stopped and introduced myself to the current owners of the home. They were very gracious and were happy to show me some issues with the home and it gave me a chance to help them with some questions they had about the home.

They had experienced some flooding of the basement space and were told they needed to install a perimeter drain around the interior of the foundation–including a sump pump. While this is a common “remedy” for concrete foundations, it should never be necessary for a properly installed wood foundation. Any water intrusion (that could not be accounted for by penetrations of the foundation like drain pipes etc) would almost have to be from failure of the installed drainage system.

A wood foundation sits on 12” of pea gravel with perforated drains to collect the water and drain it away to day-light.

Because the perforated perimeter drain continues out of the stone after it exits from under the slab, and slopes downward toward the termination of the drain at daylight, water typically would never be expected to reach the interior perimeter drain installed higher up in the stone. If the day-lighted drain becomes blocked or crushed for some reason, water can fill up the stone under the concrete slab and then come up around the slab and into the basement space.

A recommendation to install an interior drain by cutting away the floor is a very expensive and unnecessary undertaking.

I can’t help but wonder what the installers of the interior system thought when they found my installed perimeter drain under the slab. Did they use? Remove it? The correct repair would have been to figure out why the stone was not draining and fix it.

A little research about how wood foundation systems function could have saved the home owners considerable amounts of money.

Back to the addition to the home.

Note how the roof overhang on the addition does not extend past the wall as much as my design. See how the shorter overhang results in much more weathering of the siding? Large overhangs on homes can serve many functions, including protecting the siding and helping to minimize solar gain in the summer time.

By Charles Buell, Real Estate Inspections in Seattle

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