Will it rot before I do?

June 11, 2012 9:26 PM

Why am I wrong to think that the wood on this house won't rot away or become a treat for insects? [Photo links inside]

We're relocating and really like the home attached to these pictures. My only reservation is that I don't understand how the wood exterior in direct contact with the soil, covered over in large stones, won't rot away, be eaten or burrowed through. I'd like to think there's a good reason it's nothing to worry about, but the seller didn't have an answer. The foundation is poured concrete. Thanks.

Photos: 1,2,3,4

posted by roue to home & garden (15 answers total)

Can you remove the soil so that it is not in direct contact with the wood? I agree with you -- I think that the wood + moisture + soil would cause rot and deterioration over time. I'm having to replace the wood windows on my house because they have rotted through -- and the wood on those is only sporadically exposed to water!
posted by Ostara at 9:35 PM on June 11, 2012

Yes, it seems like a concern to me as well, but it also doesn't seem like an insurmountable task to regrade so that the dirt doesn't come right up to the wood (it's not as simple as just digging a trench around the house, obviously, because then you'd be encouraging water to flow right up the foundation which is bad too.) If you really like the house otherwise it doesn't seem like a reason to walk away from the deal, but consider including the cost of these repairs in your negotiations.
posted by contraption at 9:42 PM on June 11, 2012

It looks like the plywood is butt directly to the concrete foundation -- no problem with that. But you're not going to just leave the plywood bare like that, you're going to put some permanent exterior covering over it -- I don't get why they didn't run the siding down to cover the plywood.

If you are planning at all to put soil at a level above the concrete, up against the plywood, well, plan again. Or rocks, either. Anything. Nothing higher than that concrete.

And I'm interested in the plastic that is in two of the photos, which runs under the soil -- what is that about?

Who did this work, who pulled all that dirt out from next to the house, who put that plywood up, and why did they do it? If the owner says he doesn't know, he's lying to you, seems to me.

If you're going to buy it, you're going to have an inspection, and unless the inspector is brain-dead he or she will uncover anything done incorrectly.
posted by dancestoblue at 9:43 PM on June 11, 2012

I've been watching way too much Holmes on Homes lately. IANAH(ome)I(nspector), but termites can absolutely get to this wood. They'll build mud tubes to reach it.
posted by sbutler at 9:47 PM on June 11, 2012

Strange set-up there. Why do the weatherboards not come all the way to the bottom? One thing is for sure - if you have dirt/vegetation/anything up against that plywood it will be rotten in a matter of months and will provide a delicious pathway for termites to get to the rest of your house. There is some hint of a termite barrier between the concrete and the plywood (orange coloured) but it's hard to be sure. Either way, if they get into the plywood, they will get to the rest of the house. You need to keep the ground level 75mm below that plywood and inspect it regularly to look for the mud tubes sbutler mentioned.

Is is possible that the weatherboards used to go all the way to the ground but were removed due to rot/infestation? It seems there is something odd going on here and the owner isn;t being honest with you.
posted by dg at 11:45 PM on June 11, 2012

Note that the lowest boards are new, not even painted. Replacements for rotted-away boards? Is this set-up ok with local building code? It would be a red flag to me.
posted by Cranberry at 12:21 AM on June 12, 2012

It's hard to gauge the color in these photos, but if the wood is greenish then it's pressure-treated and might survive a few years. Nevertheless, this is really screwy and a significant concern.

There's more going on here than a simple poured concrete foundation. At the corner of the house in the first pic, you can see that some sort of sheet material has been applied to the outside of the foundation. The position of the basement window in the last pic suggests that the foundation goes all the way up to the siding. I suspect there was some major foundation work done very recently. Maybe some drainage problems? Severe cracking? Is the inside of the basement newly fixed up, with paneling, paint, carpet, etc. to hide evidence of old problems? Because my guess is that they excavated all around the house, slapped something on the outside for some reason, decided that the sheet product they were installing below grade didn't look so good cosmetically, and so substituted wood above grade. It's a hack job that will indeed create problems fairly soon.

Talk to some neighbors. If the sort of work I'm imagining took place, they will know about it. The fact that the seller denies knowing anything about it is worrying indeed, as the wood is clearly new, and a very recent installation.
posted by jon1270 at 3:36 AM on June 12, 2012

The wood is sun faded which suggests it has never been covered with soil. The downspout extends down below the siding as well. I don't know what the deal is with the pulled back earth but there really isn't that much of it to suggest there were piles up to the siding. More like someone did a dig-out to do some foundation sealing.

So: none of the plywood was ever buried BEFORE the dig-out. And it should not be buried now. A minimum 6 inch foundation rise between grade and any exposed wood is one of the better ways to combat insect infiltration, especially from subterranean termites.

So: make sure the foundation sill is always well above grade, except where there are windows, and you will be fine. If you don't like the look of exposed plywood and foundation, plant some shrubs or some flowers or put up a small fence. But do not allow a "bridge" of wood between the ground and the side of the house as it will be a path for bugs to follow.

I don't see anything wrong, but I would want to know what went on with the foundation dig-out before I bought, including seeing the invoices and contracts for work done.
posted by seanmpuckett at 5:10 AM on June 12, 2012

Reading jon1270's response, now I'm not 100% sure about the sun fading -- it's really hard to see what the colour of the plywood sheathing is. I am pretty sure the siding never went lower than it is now -- it all ends very evenly at a certain point -- not roughly cut off at all.

Anyway, if the plywood's been replaced at all, that's a concern. The important thing with this kind of design, though, is that the foundation sill must always be well above ground level. If the previous owner buried the sill thinking that the house looked ugly with exposed foundation and sheathing, there would be problems.

Look at the invoices and contracts and see what work was done. If the seller can't or won't produce documents for that work, that's a huge red flag about trustworthiness.
posted by seanmpuckett at 5:18 AM on June 12, 2012

I reckon that plywood is formwork for the slab that some really dopey and dodgy contractor didn't remove after the pour. Which would set alarm bells ringing. It would rot, wick moisture and be a termite entrance point. Need to have 75mm clear slab to keep termites out.

And what is with that downpipe, just exiting into the garden near the gas meter?
posted by wilful at 5:39 AM on June 12, 2012

And what is with that downpipe, just exiting into the garden near the gas meter?

It was pulled apart by settling of the soil after the foundation work.
posted by jon1270 at 5:55 AM on June 12, 2012

I don't understand why the plywood is there at all. Is your poured concrete foundation directly behind it all the way up to the siding? If so, why not just cut the plywood away, exposing the concrete to the soil? Did you clear all the soil and rocks away from the plywood just for the photo or are you doing some other work? Rocks next to the foundation would actually be good for drainage and air flow.
posted by birdwatcher at 9:32 AM on June 12, 2012

I have to agree -- plywood being here at all is dead wrong. The formwork theory makes some sense, nothing else seems to.

Without knowing what's behind the plywood, though, we're not able to help you much. If it's concealing foundation, well, it should be ripped away most likely, but there's no reason to be certain it isn't concealing an unusually low stud wall. If this is part of the house all, and the vinyl siding doesn't extend all the way down .... hoo boy. So I hope it's foundation, and if it is I don't see any reason for it to be there.

I worry about cover-up intentions (e.g. some brick veneer or what not), I worry about insulation, I worry about weather/waterproofing, and those are all issues that apply whether or not you have a termite risk in your area.

I would not buy this house, at least not without assurances from a contractor I trust who has been allowed to pull things apart and check them out. There's something pretty hinky here.

unless the inspector is brain-dead he or she will uncover anything done incorrectly

Home inspector quality can vary greatly. There's probably been some culling thanks to the housing crash, but during the boom there were a lot of pretty much mail-order DVD certifications out there. Be sure the inspector knows his stuff, and as noted I would also want a real contractor to take a look and tell me if there's a logical explanation.
posted by dhartung at 11:21 AM on June 12, 2012

I spoke with the builder who says that the plywood is "green treated" to prevent rotting. He says there's the plywood, then a layer of styrofoam insulation, and then the poured concrete foundation on the other side. The foundation itself is ~5 inches above the soil line.

Does such green treated plywood exist and would that actually prevent rot and insects?

Thanks for all the great answers so far.
posted by roue at 2:41 PM on June 13, 2012

Yes, such plywood exists and it can prevent both rot and insect infestations. The catch is that there are different levels of treatment for different applications. Ask the builder for the exact details of what product was used and check on whether it is suitable for 'on-ground' use. If so, there should be no problem, although it seems like an odd way to do things. If it has been treated to an 'above ground' level, you need to think about how you can ensure that the ground level will remain below that plywood, perhaps by establishing a gravel or concrete strip to ensure dirt doesn't end up burying the bottom of the plywood.
posted by dg at 3:30 PM on June 13, 2012