Replies

1. 
   TLE | May 01, 2012 09:09am | #1

   Not ever done that - but

   I have never done exactly as you are describing, but with a few tweakings, I don't see that it wouldn't work.

   I would use closed cell. It is water impermable and has a higher R value per inch.

   Tyvek carefully detailed should work fine - I would not use visqueen.

   Be aware that with the siding you are removing has been acting as part of the wall bracing - removing it may weaken the structure during your rehab. (That is another advantage to closed cell. It is so dense that it use becomes partially structural)

   Terry

1. 
   bnkiss48 | May 01, 2012 09:41pm | #3

   Insulating outside of house (spray foam)

   Terry:  Thank you for the information.  I had the same concerns about the wall bracing.  What I plan on doing is to remove the siding in strips, say 2 feet wide.  Rip a piece of 1/2 inch OSB and nail this back to the stud for bracing.  This OSB will also serve as an area for ladder supports while spray foaming and re-siding.  Also I plan to go the extra mile and order stainless steel nails for the siding.  The  trim I plan using a product like Azek.  The siding will be painted on all sides as well as the cuts prior to install.

   Does it matter how the Tyvek is installed ?  (left to right or up and down)  I think left to right because you can overlap and tape the seams starting from the bottom and go up like the siding. Correct?  Is this over kill?

   Great point about the closed cell type.  

   I have read some comments about insects getting into foam.  When I worked at Post Cereals in Battle Creek, we would treat the base coarse of a new cement block wall with an insecticide like Borax.  This historical home has had bugs in the past, so I think I will have something like this done.  Ever heard of bug troubles with foam ?

   Ever used an outside caulk called Quad ?  I love the stuff.  Thank you again for the advice.

1. 
   DanH | May 01, 2012 09:55pm | #4

   It's generally quickest to stand the roll of Tyvek up vertically and unroll it horizontally against the building.  And that way you have fewer seams to tape.  But sometimes it's just "any way that works" -- it can be left right, upside-down, or diagonal, so long as you tape all the seams (with Tyvek tape or "sheathing tape", not duct tape or cellophane tape).  It can even be "wrong side out" -- there's no "magic" that requires the printed side to face out (though the outside face is generally a hair smoother).

   Do try to overlap vertical seams as with shingles/siding, with the upper piece outside -- the tape SHOULD be all that you need, but it never hurts to have a little insurance.

2. 
   tntwilliams | May 01, 2012 12:51pm | #2

   concerns

   I would highly recommend using a thermal and moisture barrier that is allowed to breathe. You don't want to use a "vapor" barrier such as poly that would not allow moisture to escape. You want the water to stay out from the outside, but you want the moisture from the inside to have an escape also, not hit your insulation and sit there. 

   I would follow your thoughts of taking Tyvek or a similar product, and tack carefully to the studs and don't worry about the OSB. It is not necessary as long as when you install the siding, you nail your siding boards to the studs. If you don't hit the studs when you install you will be nailing to the insulation and eventually the siding will begin to warp and pull away from the wall. I will be happy to answer any questions if you have anything further. Good Luck!

1. 
   bnkiss48 | May 01, 2012 09:59pm | #5

   Thank you for your response.  I just remembered the studs are rough sawn oak.  I may have to pre-drill, I will let you know what happens.  I plan on painting the wood siding on all sides, including the cuts prior/during the install.  Ever use a caulk called Quad ?  I love that stuff.  I had another responder say to use closed cell foam rather than the open cell.  Any opinion on knowledge on this ?  I plan on using a product like Azek for the trim.  Ever heard of trouble with insects getting into the foam?  Sounds hard to treat once it occurs. I read some blogs on this.  This house has had bugs before, so considering having the base treated prior to foaming.  

   Thank you again

3. 
   xxPaulCPxx | May 02, 2012 01:02pm | #6

   Great article in this months FHB Houses issue.  Talks about old houses, insulation,and siding.

   Here is the problem:  Wood siding leaks water, vapor, and air.  This is fine as long as you leave pleanty of room for it to dry again.  Unfortunatly for your siding, insulation was installed without accounting for ventalation.  Old Houses NEED to breath - they were built like sponges - they absorb AND RELEASE water easily.  Adding insulation only makes it harder to release the water and encourage rot.

   So, welcome to modern building practices, we've learned alot since then!

   Now, what you need to do is this:

   Take your siding off down to the studs.  Take the windows and trim off too.  Don't worry, it will all go back on later and look like it did before, either from the inside or the outside - whichever is most important.

   Add metal crossbracing from Simpson if you think it prudent.  Cover the exterior of the studs with 2" of rigid foam, then blow new cellulose back into the cavities under the foam.  Tape the foam seams, and cover it with Tyvek/TyPAR, again taping the seams.

   Over this, run vertical furing you can attach your siding to, with a screened vent at the top and bottom to promote water exfiltration and drying.  This detail is called a "Rain Screen".  Trim your window openings out to the new depth, flash and seal a new high performance window matching your historical pattern.  Apply siding as you described and you will have a wall assembly that keeps out the elements, and will keep paint on for years to come.