Historic HomeWorks Forum

kimitchell · Joined: 28 Sep 2014 Posts: 9

Hi,
I have just started a siding restoration project at our 1870's house in Colorado. My original plan was to replace some broken boards, remove paint from the remaining siding in place, and restore the exterior. Our siding is Douglas Fir attached with square nails, and is very brittle and delicate - even the boards that are intact. As I tried to remove the broken boards, I found it was virtually impossible to remove a board and attachment nails without cracking adjacent boards. So, I decide to start at the top and remove all boards intact. See pictures. This worked reasonably well and will make paint removal and epoxy repairs easier, plus I can back-prime the boards to extend their life. Still, the top thin edge of the siding is broken or cracked on many boards

As you can see from the pictures, there is nothing in the 2X4 wall behind the siding. The interior wall is just rough Douglas Fir planking (see picture). We filled the large gaps between boards with backer rod and sealed with a chinking caulk from the inside.

I need advice as to whether or not we should install any vapor barrier, sheathing, or insulation in this wall before re-installing the siding. My read from this forum is that the prevailing opinion and answer to my question would be "NO!" to all three and "just re-install the siding." I would really love to get some opinions on this before I close up this wall as I'm hoping this area will not need work again for another 10-20 years!

A little more information:
*Colorado is very dry so we don't have much in the way of moisture problems, but the sun and dryness is brutal on wood in its own way.
*Due to its construction, this part of the house (kitchen, dining room, loft) is colder than the other section which is stone and south-facing, but we are OK adding a stove, using insulting curtains, wearing hats (!), etc., if leaving the space behind the siding empty is the best thing to do for the house.

PLEASE let me know your thoughts. I really need some validation and really want to do the right thing by this house which is a local landmark and on the National Register!

Andrea · Joined: 03 Aug 2016 Posts: 4 Location: Saskatchewan

Hi Kim,
I'm in a similar situation as of today - was attempting to insulate under a bay window, one thing led to another and now I have exposed lath and plaster from the exterior. There were woodchips in there, but they've fallen out.
My readings on this site and others is that for a balloon framed house we do not want to block the flow of air by insulating. I don't know whether yours is balloon framed.
It's not an applicable rule on my bay window, so I'm wondering whether I should put in 2" thermax or polyiso, seal with spray foam, and then close up, or what.
Anyway, I've read a little bit that exterior sheathing would be acceptable for your situation, as it's air permeable to a degree. If you've sealed the cracks from the inside with foam rod and caulking, that may be all you need.
It would be nice if someone with some experience weighed in and I'm sorry I'm not that person!
Best of luck,
Andrea

johnleeke · Posted: Tue Jul 25, 2017 1:00 pm Post subject:

Kim, Your approach so far looks good. Leave the walls empty so they will keep dry.

What was the interior finish on your interior boards? When I was in Colorado (Central City or Blackhawk) I saw some early buildings with interior boards, that originally had fabric (heavy duck or light canvas) tacked over the boards and painted, or wallpapered. This would not only decorate the surface, but significantly help keep the wind out of the living space.

Don Wagstaff · Joined: 09 Sep 2010 Posts: 102

As i understand, the principle of breathable construction/ renovation doesn't imply living in a drafty or cold or super inefficient house even one built before the principle got spelled out. What could be a problem with insulation that is compatable with the building's matrial? Well i know it from my own experiance re-roofing my house also in Colorado. The problem is avaliability of decent materials that fit the bill which explains why i have been forced to ship good insulation material from Canada here to Colorado.

johnleeke · Posted: Sat Apr 02, 2022 4:45 pm Post subject:

Don, what insulation material is it?

Don Wagstaff · Joined: 09 Sep 2010 Posts: 102

Hello John,
It's two different kinds of insulation, a stiff compressed wood fiber sheeting which is made in Germany by the company Gutex. And a flexible batting made from hemp. In fact that last one came to me from a company out of Ketchum, Idaho.