Need advice on using 4″ ext insul panels
ganns
| Posted in Energy, Heating & Insulation on
I live in New England I’m residing my entire house (30′ x 40′ Cape) this spring. I have about 100 4’x8′ foam panels 4″ thick with 1/2″ osb. Similar to the (structural insl. panels) used in post and beam construction.
I plan to wrap the entire house with these panels, install new windows and reside with cedar shingles.
Any ideas as to how to apply to panels,(strip existing shigles, patch any torn house wrap, apply panels directly to existing 1/2″ sheathing)
or (apply new 15lb felt and furring over existing 1/2″ sheathing to allow venting between existing wall and new 4″ insl panels).
Any ideas or comments would be greatly appreciated.
Thanks for any advice
R. Ganns
Replies
Hi, I've built two new houses using similar panels, so I have some ideas. I'm not an expert, but there are plenty here at Breaktime with more experience who will fill you in later.
I have to make some assumptions about your house:
1) It is drafty right now.
2) You've already got the panels and they were inexpensive (otherwise there are easier ways to tighten up and insulate an existing house.)
3) Your roof overhangs allow you to widen your house 5" in all directions.
4) You are planning on taking out the doors and windows and reinstalling them in the new outer layer, and then adding internal jamb extensions.
5) There is a solid foundation that these panels can rest on.
Given those assumptions, then I think you could do what you're planning. You will be making your house very solid and quiet. You can use 8" long self-tapping screws to fasten the panels to your existing framing members. You would want to put a layer of tar paper on the external side of the panels before installing the siding, and very thoroughly flash the tops of the panels and the window and door openings. I don't think a second layer of paper on the inside of the panels is a good idea, but I don't know enough to say either way - same thing with using the furring strips. You'll need to extend any outside light fixtures and hose connectors.
Just my ideas, I think you'd like it when you're done.
Dusty and Lefty
Greetings ganns, As a first time poster Welcome to Breaktime.
or (apply new 15lb felt and furring over existing 1/2" sheathing to allow venting between existing wall and new 4" insl panels).
Can't say that would be a recommended course of action since it would place the 4" foam panels on the outside of your venting system thus lessening the insulation benefit expotentially.
be or did I read that wrong
'Nemo me impune lacesset'
No one will provoke me with impunity
You say foam panels, what kind of foam? Probably EPS (Expanded Poly Styrene), Styrafoam is a brand name as Kleenex is for tissues. EPS is R-4.17/inch. If these are 4" thick=R16.68. not bad, I assume edge to edge coverage, covering entire exterior. Note EPS comes in different densities. A 7-11 cooler is a 1/2 lb , most SIPs and ICFs are 1 lb. A 2 lb is quite dens and wonderfull to work with. Cut on a table saw for accurate cuts. In paces that have shifting soils EPS is used as aroad base in hihgher densities.
For attachment use low expansive glue from ICF Accessories and gun. Note many glues are not EPS friendly, any solvent based glues and caulks dissolve EPS. Use 5" drywall screws with large washers to pin in place for glue set up.