Plan for zone 6 remodel roof & siding
I have read too many articles and I’m lost. I have a 1953 ranch style home in zone 6a. The asphalt shingled gable roof needs replaced. It has a hvac & ducts inside the attic, hvac touching the decking itself in a area, 3″ of height at the eaves, underventilated, under insulated, not air sealed, light mold issues and rotted rafter ends. I would like to replace it with a metal roof, soffit & ridge venting. I prefer ceiling insulation opposed to on the roof but with my eave space and thermal bridging I suppose exterior roof insulation it is. That or split on exterior and underside decking.
*Question #1: Please advise insulation plan I can hand over to the roofers as my request.
(Btw, I’m going to move the hvac out of the attic)
The current steel siding is in a decent condition. I’m told its layered over a older wood siding and buffalo board sheathing. I want it all stripped off either to sheathing or studs- whatever is advised. I want exterior insulation, house wrap, rain screen and resided. I believe I have very little or possibly no insulation in exterior walls & no plastic barrier either.
*Question number 2: please advise airsealing/ insulation plan I can hand to the siding company. My goal is a draft free warm home in good repair. I have a 100,000$ inheritance and I want to use it on this house as I intend to stay here.
*additional facts: it has a full finished poured concrete basement with the bad old way of insulating with batts & poly vapor on cement which will be fixed at some point. Seems to be a dry basement, no cracks on floor but walls are covered so I dont know about them. Tiny cinder block crawlspace as well from an addition, I’m fixing its poorly done encapsulation currently. I’m also air sealing the attic as well as crawl space. I kind of bounce from one project to another as the kids move around the house and such so I kinda have a thumb in every pie but nothing completed yet.
I’m sorry I’m just asking for you to type me out a cheat sheet. I believe I have read all the articles you are about to point out to me that have the answers I seek. My problem is often these articles will refer to multiple ways a person can do these things and I dont know which one is most suitable for me. Or they get so technical my brain starts over heating. And honestly I’ve hit this frustration barrier and I just want to beg for a cheat sheet and be released from the indecisive corner I have read myself into. I would appreciate your understanding and kindness greatly! Clearing this would be a massive weight off my shoulders. God Bless
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Trying to do a good insulation job in such a low attic is next to impossible, never mind painful. With the HVAC in the attic, I think your best is to insulate on the outside.
With metal roofing you can save a bit by eliminating the extra roof deck. It would be good to get somewhere around 4" to 6" of plyiso on the roof, if you split this so the final layer is 1.5" thick you can embed 2x4 on flat into the final layer. This would would give the roofers a solid surface to screw the metal panels into without needing and extra roof deck.
If you have only 4 to 5" of insulation in the existing attic, that can be left alone as long as you can get a bit of conditioning into the space (old leaky ductwork does a decent job for this). If more than that, you probably want to get it removed.
For a bit of extra performance, you can install mineral wool batts into the rafters. If this is something you can DIY, it will be worth it.
Since the attic is now condition, you'll need to seal the soffit area once the rigid insulation is on and insulate/air seal the gable wall.
Removing existing siding that is in good shape to insulate is hard to justify. If you have old fiberglass batts in the walls, your best bet is to dense pack over them. This increases the R value a bit but more importantly reduces air leaks. Extra insulation is best done when you need to redo the siding or doing an interior reno.
Thank you for the roofing advice. I'm definately doing the siding too. My house is very very cold and there is a hurricane of wind blowing inside my walls. I am positive I have rotting sheating in the walls due to missing flashing. Plus I have a cash windfall so now is the time to do the big projects! How do I ask for exterior insulation? Inches and which product etc?
You may want to sharpen your pencil and do the math on this project.
It sounds like you will be redoing everything with even a small amount of job creep. When you open up that many walls you are likely to find a surprise or 2 and generally they are not pleasant.
You have roof, siding, HVAC and insulation on your list. If you are doing the siding it is almost silly leave the 67 year old windows and doors. The electrical is so old and likely undersized for today, with the walls open now is the time. Is the wife going to be happy with you spending a ton of money on the house and she has to live with the old kitchen and bath?
Maybe your neighborhood could support that type of remodel but most will not should you need to sell. The stuff on your list adds almost nothing the resale value of the house
Consider blowing the walls full of cellulose, moving the HVAC to the basement, pull the roof sheeting to air seal and insulate the wall then reroof.
Walta
None of this is being done for resale value. It's being done because I want it for me and the hopefully 50+ years I will be living here. I havent a wife to worry about, I am the woman of the house and sole owner. And I want exactly as I listed I want. I do hope to find those ugly surprises honey. That is the whole point here. Roof, siding. Hvac knock em out big and knock em out right now. Any exterior insulation advice to go up while siding?
Good for you, Trina. Thumbs up. And don't tell the contractors you've had a windfall.
With a 2x4 wall, assuming it is insulated to roughly R13, in zone 6 you would like to have R7.5 exterior insulation to avoid needing an interior vapor retarder.
That is 2" of EPS or 1 1/4" of polyiso. 1 1/2 polyiso w0uld be better as there is some R value derating at colder temperature.
To keep the siding install simple, If you go with 1 1/2 of rigid, most light weight sidings can be nailed up directly through the foam, much cheaper install.
You can go with more insulation, but you will be hitting the law of diminishing returns quickly. Most cold climates, anything much above R25 is not worth it, so in your case that would be 3" of insulation of exterior insulation. With 3", you are now in the territory of long screws for the rain screen, which lot of builders would not be comfortable with.
Trina,
I think Akos has a good plan for your walls with the addition of blown cellulose (if currently uninsulated) in the walls. You can remove the existing siding (leave sheathing) and fill the walls from the outside. Apply the 1.5" Polyiso over the existing sheathing and tape the seams. This will give you an airtight and quite a high performance wall.
For the ceiling air sealing and insulation I would propose the following. Remove the HVAC and relocate to the basement as proposed. Evacuate the current insulation in the attic. Add ventilation chutes from the eave side as you will be reinforcing rafters tails and will have access. Make sure the new sheathing (Polyiso) fits tightly around the air chutes between the rafters. Find an insulating contractor that is spraying the most environmentally friendly 2 part foam and flash foam (1.5" or so) the ceiling. Make sure to get full foam at the exterior walls under the air chutes. Add blown cellulose to bring attic insulation to code. Ventilation should be at both the eaves and ridge.
Thank you all so much, I appreciate it!