Hi there to all. I’m new to this site and I have a pressing issue. I recently bought an 11 year old house in Bend, Oregon and am making changes, including the exterior siding. Right now it’s some sort of 4×8 sheets of pressboard stuff and in some areas has water damage- swelling and other damage along the bottom edge. The only thing between the siding and the framing is housewrap. I want to change the siding to Hardiboard planks, replace the windows and add a window or two.
The designer that is helping me with the plans thinks the new siding can go up over the existing and I’m thinking it would be better to pull the old down, put up an underlayment layer and then the new siding and windows. I realize that will be more expensive and time consuming, but I want it done right so I (hopefully) don’t have to worry about it.
Am I right, or am I going overboard?
Replies
I don't think you are over doing it. It is not wise to cover over and trap rotted materials inside your walls. All siding leaks at least a little bit, and the material you trap will continue to rot since it is so prone to damage from water. There may also be hidden damage under the siding which you'd never know about if you did not remove it all. There might have been a leak around a window or door, or just general damage from the rotting siding.
There is also more difficulty making all the trim work out when you add another layer of siding thickness.
If it were my house I'd take it all off and start fresh.
It sounds like your siding is similar in function - if not form - to T-111 plywood. This is usually 5/8" thick plywood with vertical grooves either 4" or 8" on center. There are some OSB-like versions of this material. It serves as both sheathing and siding. There are often water problems with these materials because it is difficult to flash properly around doors and windows.
I'll disagree with the earlier poster. If this material is mainly structurally sound and well-nailed, it is providing the vertical rgidity to the structure. It would be a major project to strip it all off. Any bad spots can be cut out and patched. Then, you can install new house wrap, windows, FLASHINGS, trim and siding.
Al Mollitor, Sharon MA
(Breaktime truant)
I would strip it off, sheath it with 1/2" ply (get 5 ply CDX doug fir....easily available here in Oregon).
My folks lived in Bend till Dad passed on a couple of years ago....same siding as you describe....I stripped it and sheathed it as above and put up Certainteed F/C. Wasn't that difficult and it gave us the opportunity to trim the exterior of the existing vinyl windows out with brickmold, sills and stools.
Bend has a somewhat arid climate, but it can get wet and windy and humid at times like other areas of Western Oregon....and because of those conditions, I'm a firm believer in doublewall construction and good flashing and trim here in the PNW. It's time, effort and money well spent IMO.
Hi Roni.
If the siding is some type of pressed wood, instead of plywood, I too would be inclined to pull it all off. However, if only the near-ground contact areas are showing signs of rot, you could as earlier suggested, cut out these sections only and replace.
Have you considered the possiblity of just fixing the bad spots, then covering this siding with felt paper, then attach furring strips to the house structure and then attach your FC board to the furring? What I just described is a "rain wall" at least, I think that's what they call it. Point is, is that the furring allows any water that gets behind the FC a way out, and the FC will dry out quickly, and the original sheathing will be able to also stay dry.
Doing this type of construction would allow you to keep your original sheathing in place, thus saving time and material... plus the small cost of the furring will give you added protection against water infiltration, and this type of wall construction would be easier to build instead of tearing everything off and starting over.
The only drawback to this rain wall construction, involves padding out windows and doors...but you earlier said you planned to change out your windows and doors anyway, so again this type of construction might be the ticket.
Just a thought.
Davo