The "Changing an R11 House Into an R24 House Project

[MountainDon]

Is is now too hot to work outside anymore today.   

That is the wall rating for the insulation. Our mid 80's built house has 2x4 walls with R11 fiberglass that is pretty standard for the time built. I started the project in early spring 2012 I'm nearing completion of stage two of three. The end of the house that was done last year was warmer in winter and cooler in summer.

I just discovered I left the camera at the cabin. The DumbPhone takes lousy pictures so images will have to wait a week or so. Basically this was a continuation of the previous method.
Break and remove old stucco.
New weather resistant barrier installed.
Install a layer of 2 inch XPS foam on exterior. (R10)
Install a foil faced layer of 1/3" polyisocyanurate foam over that, with staggered seams. (R3.2)
R value increase will be better than the numbers add up to as the foam bridges all the studs.
Tape all seams, caulk where necessary.
Install furring 1x4 on the 16" OC studs. Screwed through the foam to the studs using 6 inch Headlok screws. I love those screws. They have a spider or Torx drive and simply do not slip. No need to keep heavy pressure as you must with Philips screws.
1x6 were used around the new windows to provide fastening surface for trim and lap siding.
Installed LP Smartside trim, 4" wide.
The last step is almost 6/14 done; installing LP Smartside lap siding. Priming all cut edges as I go along. Hand nailing with ring shank hot dipped galvy nails.
Final step will be two coats of paint on the pre primed lap siding.

Images will be posted later I hope. Much the same process as in phase one, except I went with 2" XPS this time instead of 1 1/2 " XPS as in phase one. (plus a 1/2"polyiso both times)

The new windows also meant all new jamb extensions, window sills and trim on the inside.

[MountainDon]

The Headlok screw people have a document online with instructions and a table that shows how many screws are needed depending on the spacing of the furring strips and studs and the weight of the materails to be used as siding and the thickness of the foam. I have used a lot of screws. Good price on buckets of 250 from Amazon.

[MountainDon]

I just realized that if I work on this tomoprrow I won't have any half way through pictures... so here goes a couple of DumbPhone images. The first is shot down the rear wall with 6/14 of the lap siding done.  That is a temporary post as the original was too close to the house and window to do any work.



and the second illustrates how I got around the hose bib. It is a frost free type. I did npt fancy unscrewing it and trying to reinstall a longer one. I also has worries about twisting it off or breaking the pex fitting free of where it is supposedly nailed to a stud in the intersecting wall. So I decided the better approach was to box around the bib. So what if the wall insulation remains r11 at that poiint. The hose bib still will not freeze and I avoided the possibility of having to mess around with cutting into an interior wall and doing something with the PEX.

[grover]

Curious as to how the extra wall thickness is handled around the windows and doors.  Sounds like approx. 3 inches of extra thickness has been added to the wall. Do you have a thread where you are detailing the process? 

[MountainDon]

I will describe the process used as I never did take any photos being absorbed in the project as I was or having forgotten the camera at the cabin. After the old siding (stucco) had been removed the old windows were removed. I ripped 2x's tp what the thickness of the foam would be. Those were then secured to the wall studs, headers and sill 2x's with Headlok screws. Even though Headlok states there is no need to drill pilot holes I did for these pieces. I did not bother drilling for mounting the furring strips later. One every 12" around the perimeter. That framework was flashed with Grace Vycor Plus flexible self stick flashing. from the exterior new 2x face wrapped into the opening and to the original studs, headers.

There are other ways using plywood "boxes" built to fit inside the original framing.

Then the rigid foam sheets were installed, 2 layers, seams staggered using the special washers noted in the other thread I mentioned/linked to previously. Six to 8 screws per panel. The furring strips do the real securing. Screws and washers were for temproary as I took a while to work through the process.   1x4 and 1x6 furring installed vertically and at windows the bottom and top too. (1x6 at windows and door.) The 1x's were also flashed to the opening. Then windows installed; vinyl finned type, energy star rated good enough for tax credits. Which I could not get as we had reached our limit on windows and doors previously. Window fins done with Vycor final flashing. That stuff comes in many widths. I think I used them all.

Then windows trimmed with 5/4 by 4 inch wide. This morning I have reached the tops of the windows with the lap siding. It is now too hot to do anymore outside. That wall gets full sun until about 2 PM. I have to cut to fit the siding at the window tops. That I think I can do in the shop.

[dablack]

Very Cool (AC joke)!

I don't know if I would want an "outie" window or a midmount.  I can't decide.  I think a slightly protected window would be nice. 

If you can find a deal on the foam or get it used, I would for sure do this.  Thanks for the pics and explination.  I have read about this method many times and seen "how to's" but no details from an actual install. 

Austin

[archimedes]

Interesting project.  I'm in the planning stages of doing the same to my house.

What,  if anything,  did you use to close off the bottom of the air space behind the siding?  If left open wouldn't bugs or small rodents get in?

Also,  I'm debating vinyl vs aluminum windows,  any reason you chose vinyl? 

[MountainDon]

Windows, in n, mid or out... I believe it is easier to do a great flashing job with the windows out.



The top and bottom between the furring strips is all screened to prevent insect incursion but to allow for any possible water to drain.

Vinyl because we have a local manufacturer of excellent vinyl windows.

[MountainDon]

I meant to point out that the local made windows were an attraction because the sealed dual pane units are then adjusted for the 5500 foot altitude. Windows from lower altitudes, where most windows originate, have seal failures here earlier than when the windows are made at or near the installed altitude.

[archimedes]

Do you mind if I ask what the LP siding cost per board? 

I believe it comes in 16 ft lengths,  what width did you use?

Thanks

[MountainDon]

16 ft, 8 inch wide (actual is slightly under)  $8.05 each plus $20 delivery

[Don_P]

Going back to the windows at altitude comment. In the early 90's we had multiple windows crack a little above 6000' on several jobs, we had a local company do the warranty work. We saw several before they broke that looked "funny". Since then many manufacturers have a capillary tube that supposedly balances the pressure, not sure how well that works as I've been east since then.

BTW, still raining here, 13"+ in the past 2 weeks

[MountainDon]

... a capillary tube that supposedly balances the pressure, .....

Right about the tubes. I had forgotten. But also have no idea on how much help that is. I think there must be some validity to it as most new windows installed here are not locally made and do not seem to have an unusual failure rate. In any event buying local is good when the product is of great quality overall.

BTW, still raining here, 13"+ in the past 2 weeks

Wow!! We have made it to an inch in 2 weeks if I do some rounding up.    And we think we're doing okay, but not great.

Read some info that some of the local (LANL and Sandia NL science folk believe by 2050 the NM conifer forests will only have about half the tree density as today. Good in a way as most are presently too dense. But bad as they believe that by 2100 the local conifer forests will be gone.

[kashata]

Just curious how the LP smartside is holding up over the furring strips...i.e., are you noticing any cupping, bowing, etc.  I want to construct the same way but a number of builders indicated possible problems placing the LP smart side over furring strips, over rigid insulation...due to the thin 3/8" size.

Thanks

[MountainDon]

No warping, cupping, bowing, etc happening. Still looks like it was just installed.