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Let's totally rip out and rebuild something together.
September 4, 2011 8:32 PM   Subscribe

What is the proper way to replace rotted siding and fascia (looking for someone to enumerate the layers and materials) so that the house is well sealed and weather protected?

I bought a 1950's era house Thursday. First homeowner job was to replace a 30"x10' area of lower wall which had been severely rotted away by previous owner's great idea of putting a raised flowerbed against the house. Curb appeal *sigh*. I pretty much just replaced what was there, but with modern materials. Now that it's done, can someone tell me if I've done anything wrong? Perhaps I should have come here first.

* Stapled a single cut sheet of Tyvek over the framing.
* Nailed lapped board to fill the space using 2.5" box nails.
* The boards were a bit warped and didn't fit well (best I could do with Lowe's lumber) so I sealed all crevices using Great Stuff foam.
* There was a strip of aluminum flashing (but so thin I thought it was actual tin foil) at the top of the previous wall, so I used a strip of Tyvek instead. This felt dodgy.
* The outer siding was then cut and nailed on using 2.5" casement nails. All crevices and nail holes were sealed using painter's caulk.
* I paint it tomorrow.
posted by hanoixan to Home & Garden (3 answers total) 1 user marked this as a favorite
 
Not a carpenter, not your carpenter, just a DIYer/handyman on four rental properties.

I hate to say this, but I think in the long run that first layer of Tyvek may have been a mistake. It's a weather barrier, which means it prevents moisture from getting through, but you have sandwiched your underlayment between two moisture barriers. That can encourage rot.

Next, I'm not sure what you mean by lapped board. Did you install clapboards with overlap, but no flat sheathing? See the lower diagram here. The typical material used for this in modern construction or reno is OSB (superior to plywood for these applications), with thickness for different applications specified by code (e.g. wall sheathing doesn't need to be as thick as roof sheathing because you don't need to walk on it). OSB sheathing comes with a notched edge so that you get a shingling effect that will drain properly if any moisture gets into it. Now, your "lapping" may have the same effect, but generally I understand that in residential applications wooden or composite siding by itself and no sheathing would be a violation of code. Maybe you meant by lapped that you purchased a sheathing material and this is OK after all. As to matching, it's your job at the lumberyard to pick the flattest and straightest-cut panels. If they are flat and straight and don't fit, you may have installed them incorrectly. I'm worried about your statement that there were crevices, because even if you had the right material, you can defeat the purpose of the fitting.

The Great Stuff will help with air intrusion, but over time will be vulnerable to moisture intrusion. You don't mention any in-wall insulation.

Tyvek is probably not acceptable per code for flashing applications. I think that needs to be a rigid plastic or metal material.

The rest seems OK, but while what you've done may not necessarily warrant ripping out, I would want to watch it carefully over the next few years for any signs of rot or other moisture effects such as mold.

Did you take any photographs of this work in progress? The building inspectors -- on jobs requiring permits, which cladding isn't where I live -- like to see things before they get covered up, but it sounds potentially too late for that.

There are numerous books on framing and exterior repairs that will show you how to do this right, with color photos even, and you probably breezed right by the bookshelf at Lowes where they were on sale. Don't skip that step next time unless you're sure you know what you're doing. Get yourself a good book on general home repairs now that you have other projects to tackle.
posted by dhartung at 11:02 PM on September 4, 2011


That's a great answer. Thanks dhartung! I think this was a great lesson in doing something too fast and not researching. Luckily it's a small section of the wall that shouldn't see much moisture. I did see those books, and I will be purchasing one asap.
posted by hanoixan at 5:54 AM on September 5, 2011


I assume by "lapped boards" that the house wasn't originally sheathed with plywood but probably tongue and groove pine boards which you replaced with pine boards that have lapped edges... probably reasonable, or at least more likely to match the original thickness of the sheathing. the purpose of sheathing is to make the frame of the house rigid, for such a small section it probably doesn't matter so much. I also assume the flashing was an attempt to proect the house form the planter boxes, so it's not necessary if you've gotten rid of the boxes. The misapplied Tyvek is a long-term thing... I would be worried about two things:

1) are "casement nails" the correct fastener for the siding you are using? if you are using wood siding the answer is probably no. (i don't know about cement board stuff) if your casement nails are what i think they are you might consider some siding nails: DON'T USE "COMMON NAILS."

2) is your "painter's caulk" rated for outdoor use? if it's the stuff at home depot called "painter's caulk" the answer is no... if it is that stuff, honestly, you are going to find that in a month or two (or sooner) the caulked edges or cracks have started to become visible as the caulk rapidly degrades.

I mean, the thing about this is that most of the problems (aside from air sealing which you did, yay!) are going to be cosmetic. you might check on it from time to time to check if water is somehow getting behind the siding you installed i.e. stains, bubbling paint, warping. at this point, the worst case is probably having to tear it out and redo it in a couple of years.

also,

As to matching, it's your job at the lumberyard to pick the flattest and straightest-cut panels. If they are flat and straight and don't fit, you may have installed them incorrectly. I'm worried about your statement that there were crevices, because even if you had the right material, you can defeat the purpose of the fitting.

the lumber at home depot now seems to be largely junk, even by already low home depot standards even the plywood is now bowed and warped. often enough i think it's actually impossible to find usable lumber there.
posted by ennui.bz at 6:20 AM on September 5, 2011


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