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I need to hang insulation in a crawl space but the beams are ~6' apart (with 1 1/1" T & G decking running perpendicular). Any ideas to keep from sagging in the middle? I have heard of others using lathe run across the beams - they claimed it was better than wire. I think I have seen little wire extenstions that I could screw into decking between beams (then attach wire to those)...but I don't remember where I saw them or what they are called (nor do I know if they are the best solution). To make matters worse, beams are about 7" deep and because of tight space I really don't want insulation coming any further down than necessary.

Thanks in advance.
 

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Curmudgeon
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I need to hang insulation in a crawl space but the beams are ~6' apart (with 1 1/1" T & G decking running perpendicular). Any ideas to keep from sagging in the middle? I have heard of others using lathe run across the beams - they claimed it was better than wire. I think I have seen little wire extenstions that I could screw into decking between beams (then attach wire to those)...but I don't remember where I saw them or what they are called (nor do I know if they are the best solution). To make matters worse, beams are about 7" deep and because of tight space I really don't want insulation coming any further down than necessary.

Thanks in advance.
Put down a vapor barrier,
and insulate the perimeter instead.
Problem solved. :thumbsup:
 

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Discussion Starter #4
Thank you for the replies...

Thank both for the replies...there is more involved than I shared (I was trying to give the basics as I have decided the best option is hanging insulation attached to/against sub-floor). So I am really just trying to see if others have found a 'better' way to hang insulation across long spans.

Put down a vapor barrier,
and insulate the perimeter instead.
Problem solved. :thumbsup:
I had considered this and man would it be easier (even more so since I will be putting a vapor barrier down anyhow). But I would rather not heat the entire crawl space with the radiant.

string stapled to the bottom of the joists is what I've seen on smaller spans. Not sure if that would work. Maybe wire instead.

Spray foam would work great on that.
I had considered spray foam but the cost is pretty high - and I would still need to put a layer of aluminum or some other heat conductor to dispense the heat from the tubes (aluminum 'planks' are pretty spendy). So I was hoping to use aluminum faced insulation so I could do it all at once.

If price were not an issue, I would in fact have done the planks with spray foam afterwards...

So wire still may be my best option...

Thanks again.
 

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Curmudgeon
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Insulate the perimeter, and
staple reflective under the joist.
That aluminized bubble stuff
comes like 4' wide.
All you need is a reflector,
heat rises.
 

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Discussion Starter #7 (Edited)
Insulate the perimeter, and
staple reflective under the joist.
That aluminized bubble stuff
comes like 4' wide.
All you need is a reflector,
heat rises.
Neo...Thank you, this will definitely be my method if I don't end up hanging the insulation.

spruce strapping
Thank you Smith...I hadn't even thought of 1 X material. I have had trouble tracking down lathing that is 6' long. I was figuring I would have to rip 2X stock down - which I was not looking forward to. I should be able to find 6' or maybe even use 12's, and I could use the cheap 1X2s...this is great.
 

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Discussion Starter #9
Treat it like a trailer - landscape fabric / plastic / whatever is used up there pulled tight - staple it & blow with fiberglass
Hmmm...hadn't thought of blown-in either. If I have trouble finding foil-faced insulation (one step) and have to put up 'foil' and then insulation, this will definitely be an option (would probably be best - except for spray foam - for tight seal.

Thank you.
 

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Put down a vapor barrier,
and insulate the perimeter instead.
Problem solved. :thumbsup:
I plan to to this with spray foam. You're referring to the exterior walls right?

Insulate the perimeter, and
staple reflective under the joist.
That aluminized bubble stuff
comes like 4' wide.
All you need is a reflector,
heat rises.
I don't think you'll gain much with the RB other than to hold up the FG

Insulating a floor over a crawl is mistake. Insulate the perimeter.
I already have FG in the floor joists. Should I remove it and just spray foam the walls?
 

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Curmudgeon
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I plan to to this with spray foam. You're referring to the exterior walls right?
:thumbsup: Exterior walls=perimeter.

I don't think you'll gain much with the RB other than to hold up the FG
If the perimeter is insulated there is
no fiberglass in or under the joist.
(Except in the perimeter pockets
and along the rim joist)
The OP was dealing with in floor
radiant heating, therefore the heat loss
he was worried about was radiant heat.
The reflective barrier should be
just the ticket for him, once the perimeter
is taken care of.



I already have FG in the floor joists. Should I remove it and just spray foam the walls?
That's ideal, in conjunction with
a vapor barrier on the crawl floor.
 

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:thumbsup: Exterior walls=perimeter.



If the perimeter is insulated there is
no fiberglass in or under the joist.
(Except in the perimeter pockets
and along the rim joist)
The OP was dealing with in floor
radiant heating, therefore the heat loss
he was worried about was radiant heat.
The reflective barrier should be
just the ticket for him, once the perimeter
is taken care of.





That's ideal, in conjunction with
a vapor barrier on the crawl floor.

Ah, Im missed the radiant heat thing. Thanks for clarifying that. I was considering that as well

I put FG in the floor and an VB down many years ago. Why would removing the FG be benefical?
 

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Curmudgeon
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I don't know if it's worth it
to you since it's there.
The idea is that you are creating
an envelope that includes your
plumbing and duct work in the
conditioned space of the house.
It's also less insulation
for the same effect if you're
starting from scratch.
 

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I don't know if it's worth it
to you since it's there.
The idea is that you are creating
an envelope that includes your
plumbing and duct work in the
conditioned space of the house.
It's also less insulation
for the same effect if you're
starting from scratch.

Yea, that makes sense.

Thanks!
 

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My crawl space is about 50' long and 12' wide. It's adjacent to a full basement, but there's a non load bearing wall separating them. The boiler keeps the basement pretty warm in the winter. Should I open that wall up to the crawl space?
 
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