insulating behind old redwood double-lap
My old 100-year old cottage in Pacific Grove, CA has been gutted, remodeled, and is about to be insulated for the first time ever.There’s no moisture barrier between the old siding and the studs and the back of the siding has water satins. Rain’s blown through the cracks over the course of the years, but obviously dried out as there’s not a bit of rot.
Mold’s a problem in this foggy coastal environment. I’m concerned about new insulation getting wet and creating a nice home it. I thought about sealing the back of the siding with some sort of thick elastomeric coating, but then the walls don’t breath. I thought of not sealing it, but creating a air channel between the siding and the insulation.
Any thoughts on whether sealing the siding is good or bad, the type of insulation to use (fiberglass, cellulose, poly foam, etc.), air channel?
Regards – Drew
Replies
Dear Drew,
Here in Illinois I've the same or similar problem. Right now I have house wrap laid into the stud space and lapping two inches onto the faces of the studs with tyvek tape holding the edges to the stud faces. BUT I don't know whether I'll have enough brethability in there. Am in the middle of trying to find out. I posted my Illinois problem two days ago and haven'y heard from anyone. Hmmmm...
I may end up taking the wrap out and suffering the wind.
crawdaddyjack
Dear Drew,
Here in Illinois I've the same or similar problem. Right now I have house wrap laid into the stud space and lapping two inches onto the faces of the studs with tyvek tape holding the edges to the stud faces. BUT I don't know whether I'll have enough brethability in there. Am in the middle of trying to find out. I posted my Illinois problem two days ago and haven'y heard from anyone. Hmmmm...
I may end up taking the wrap out and suffering the wind.
crawdaddyjack
craw&drew-I'm just a DIY homeowner but what I did was nail 3/8" or so woodspacers on each side of the wall studs touching the backside of the sheathing. I then took the black fiberboard celotex insulation 4x8 sheeting and cut it to fit between the studs touching the 3/8inch spacers thus providing a rain vent where any moisture that might enter in there had a way to breath out and still get my wind break and a tad of insulation to boot. I cut them slightly oversize and hammered them in with a friction fit between the studs. If you really wanted to do it up you could put a bead of caulk on the spacers before placing the fiberboard to really assure an air barrier.
It's a bit labor intensive but the house holds the heat really well.
I believe the fiberboard is water permeable so I wasn't too concerned about forming a double vaporbarrier. I did drill 1/4 holes in the top plate of each stud bay on the in side of the fiberboard to provide another place for moisture to breath to in the event any got in there to the fiberglass batts. I then put 1/2 inch foilback celotex foamboard over that and taped the seams for a vaporbarrier.
I considered the tyvex but opted for this configuration since it seemed more solid and added R-value. Keeping the wind off of the fiberglass batts helps the glass preform better.
What kind of siding is on your place? Reason I ask is I was wondering if you'all have any racking problems associated with the thinner clapboards that have no sheathing underneath?
Character? I never had any problem with character. Why, people've been telling me I was one every since I was a kid.
Edited 12/31/2002 12:17:21 AM ET by rez
Rez,
It's half lap redwood siding commonly called double-lap here. It's 1x8 with 2 laps per board--and yes, racking was a problem. This old house was so out of plumb I had to take a come-a-long to it and add some shear here and there to straighten it up. It's withstood a few good sized earth-quakes in it's time, so I suppose there's something to be said for the old style construction. Call it flexible strength. The exterior studs are 2-1/4" and the interior studs are 1-3/4". Build by the American Bible Society. A frugal lot I recon.
Drew
Ok, after I insulated with the fiberboard and fiberglass batts I covered the walls with 7/16 or 1/2"plywood on the studs. Then a layer of celotex foilback Tuff-R foamboard and taped the seams with foil tape for a vapor barrier then drywalled for fire protection. I figured the plywood would help stabilized the racking effect. How far along are you on the project?
This is a total first time DIY project with worn shoelaces for a budget so you got to cut me some slack. Otherwise known as the house of salvage.
I posted some pics of the raw house in the thread ' dozer salvage house' a while back. I took off the old asphalt impregnated fiberboard insul-brick stuff that was so common in the 40s or 50s and sanded the redwood siding to bare wood then coated with a Behr oil preservative with the UV inhibitors and antimold stuff.
Here's a pic of the progress back then. The siding closest to the camera is the original 1908 and the bump out closet/bath area I added to the back has the 1x10 redwood siding I salvaged from an old timberframe that was being torn down. It was covered with vinyl before I got it and I inverted the painted side to the building , cleaned up the bottom lip and did a light sand on the exposed surface. Then added a couple coats of the oil to it. That's why I asked what type of siding you had on there in case you didn't want to paint it.
Forget 'prog'. pic. I messed up on the download.
Character? I never had any problem with character. Why, people've been telling me I was one every since I was a kid.
Edited 1/5/2003 12:11:53 AM ET by rez