A portion of my sunporch is over an open crawlspace and I’m tired of the freezing floor and general lack of comfort in this space. Would I be better off cutting foam to fit between the joists, sheathing them and blowing cells, or a combo of the two? This is in windy NNJ.
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I've done a few of these with fg between the joists and pink ins board over, then stapped and covered. All joints tyvek taped first too.
I forgot to mention that termites are a problem around here and that there is the biggest groundhog I've ever seen that has a vacation hole under there. I only see him around a few times a year, no idea where he the rest of the time.
I think the in-laws lake house was done that way, hard to tell as it has PT plywood over it.
Under ours (a raised "3-season porch" incorporated into our deck) I fitted fiberglass batts, then made wood "screen" frames to fit underneath and covered them with hardware cloth and landscape fabric. The screening keeps out the varmints and cuts a lot of the airflow, while allowing things to dry if rain blows in. The panels are removable to allow access in case something falls through the deck boards, etc.
Particularly in a termite zone, I would avoid using foam board under the joists. In any case, unless it's EPS, and not XPS, it won't breathe.
And though I'm no fan of fiberglass, I would second the recommendation to use batts and then seal with hardware cloth and filter fabric. That's how I've done it as well, though fixed in place not in panels - it keeps out insects, rodents and wind and lets the cavity breathe moisture.
Solar & Super-Insulated Healthy Homes
Edited 12/30/2008 5:19 pm ET by Riversong
I had thought of trying borate-treated foam, but I'm not aware of a source locally. Can you explain the second part of the last sentence, "though fixed in place not in panels - it keeps out insects, rodents and wind and lets the cavity breathe moisture."?
Can you explain the second part of the last sentence, "though fixed in place not in panels - it keeps out insects, rodents and wind and lets the cavity breathe moisture."?
I mean, rather than making up removable screened panels, it's much simpler just to staple up rolls of filter fabric and hardware cloth.
And that combination, while keeping out critters, bugs and wind will still allow the floor assembly to breathe and drain in case it gets wet.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
I'll add that you do need to be fastidious about sealing every hole -- add flashing or blocking to gaps that are too awkward for the cloth -- so that critters can't get in anywhere.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
Ah, ok. Any recommendations on the filter fabric? I have some Insulmesh that I'm using for the soon-to-be Mooney walled painting studio/bedroom/dump.
Like I said, I used landscape fabric. It's weather-resistant and blocks air pretty well but lets water through. And it's cheap.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I like cheap these days, especially where no one except the groundhog will see it.
Ditto on the landscape fabric. But avoid the cheap rolls for gardening, as they are not very tear-resistant. I use roadbed fabric which is very strong and dense, yet still breathes.
I would NOT use plywood and cellulose (even though I am a huge fan of cellulose), as it may not be possible to keep it dry and the plywood would just trap the moisture.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Close it off with plywood. Make sure it stays dry. Blow full with cells.
But If you have no heat in there it won't stay warm.
mv...... is this an enclosed porch ?
why is there a concern about the insulation getting wet ? can it get wet ?
if it can't get wet then it affects the recommendations of how to proceed
if you want to use a treated foam ..... google on
R-Control for the nearest franchise that makes PerformGuard
if the joist space will remain dry , i'd use 1/2" PT ply and blow the joist bays with cells
if it tends to get wet.... what is the route the water follows ?
from the top down thru the flooring ? or from the sides ?
if you use untreated foam or fiberglass there is no way you can keep the mice out
no matter what you do with screening or fabric... mice will get in
unless you use a treated product
I read the original description of "sunporch" to mean closed in by windows. Which leads me to recommend cellulose as well.I've done this in non-termite zone, sheathing over the joists with 2" Polyisocyanurate and blowing cells in behind it, but after a recent invasion of carpenter ants nesting in it on another job, I think I would avoid the foam in a exterior application like that. Cheapest would be to to skin the bottom with the insulmesh and DP the cells.Steve
Edited 12/30/2008 7:38 pm by mmoogie
To make things clearer, the space I'm talking about is to the left of the living room shown here. http://books.google.com/books?id=SFIAAAAAYAAJ&pg=PA17#PPA14,M1It's 2x10, 16" OC framing open to the soil, built on brick piers. Back in the forties they did a goofy remodel on the place after a fire, enclosing previously exterior spaces, but not doing a thing about weatherizing them. Any wind from the north will cause a 10 degree drop in certain rooms within minutes. No, it doesn't get wet from the top, it's inside with a finsh floor, heated by a giant, low, cast iron steam radiator.
Edited 12/30/2008 9:14 pm ET by MVAgusta
well.....
based on that....
i'd nail up 3/8 or 1/2 PT ply to the bottom of the joists... this would be tough enough to dissaude most rodents and would not support vermin
then i'd blow cells... you could blow thru holes cut with a hole cutter bit, and the nail PT squares over the holes
the PT will stop the big rodents, and the borate in the cells will stop the mice
9" of cells will stop a lot of cold.... the only weak point will be the thermal bridging of the joistsMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Thanks for the ideas. Also, thanks for all of the project posting you'vedone, very useful info, I'm Mooney-walling everything that's practical from now on.
Cool. Is that the actual house in the photos following the floor plan? Does it still look anything like that?Steve
That's it, the interior is mostly there, just a lot of loose sand-float plaster that needs to be patched. I swallowed up the back porch for thekitchen and added a bathroom where the pantry is shown.The exterior is pretty rough, the house had a cedar roof that they covered with 3 tabs, even the vertical spaces and the dormers.
Nice! Those three tabs are slated for the dumpster I hope...
Yeah, but I don't know what to do for roofing after that, cedar would be appropriate but would look terrible after a few years of the air around here. I've been eyeing the Nichiha shingles for the sidewalls, dormers and vertical spaces, then maybe dimensionals for the actual roof. Any opinions out there are welcome.
Off topic alert
do you have one of your screen namesakes products.....vroooommmmm?
(and I don't mean the helocopters)
Nope, can't afford one. I was always more a fan of the race bikes anyway, but I do have a 77 BMW R100RS with Krauser heads, those get a lot of strange looks.
To some extent there wasn't much difference between race & road with AgustaThe Beemer sounds very sweet....I had a'70s R75, and then an 80's R80. I've ridden the brick, the new twins, and the triple (one of the best, IMHO)
I think they kind of lost their way when they started doing retro & chopper stuff.Back when I was into it, and wanted the latest goodies but couldn't afford them (not so different now, really) I would have died for those Krauser heads......Post a pic?
I'll have to find one, I'd take one now but it's buried behind the 4'x8' Marvin that's next on the install list.
check out Airkrete, it isn't cheap but may meet your other criteria
www.airkrete.com/
Cool product, but it looks like I need to be an installer or find one around here, my foam guy just does the NCFI foam, the green/blue stuff.