Insulate crawlspace ceiling below office floor?

[shetc]

Hi All,

Here is a picture of the crawlspace ceiling, right beneath where my home office desk is located. My feet get very cold right there. Would insulating the ceiling under my desk area be helpful? Or make things worse?

Thanks,
Steve

 

[bruce_the_loon]

Based on my experience watching Mike Holmes repeatedly fix problems like this, the answer is yes.

He always discusses thermal breaks to isolate the interior from exterior spaces. Since this is a crawl space directly on soil, then you would definitely have a thermal loss happening, more so if the crawl space is not sealed against outside air flow.

Thermal spray foam would be the easiest, but probably not cheapest, way to insulate. It sticks and fills all gaps if applied correctly. Fitting insulation like you have between the floor joists would work as well, but you'll have to stick boards of some sort underneath to hold it in place and ensure there are no gaps.

 

[mac_1103]

Can't really tell if the crawl space walls and floor are insulated or if that's just a vapor barrier. Probably just plastic sheeting on the dirt, so yeah, I'm gonna say you need to insulate.

 

[Erik the Anglophile]

Just slap some rockwool in there and maybe some 1x3 or something across to hold those itchy a-holes in place.
/Professional builder.

 

[shetc]

Can't really tell if the crawl space walls and floor are insulated or if that's just a vapor barrier. Probably just plastic sheeting on the dirt, so yeah, I'm gonna say you need to insulate.

No insulation just plastic to prevent damp from the ground.

 

[shetc]

Just slap some rockwool in there and maybe some 1x3 or something across to hold those itchy a-holes in place.
/Professional builder.

Thanks, Erik! Insulate the whole crawlspace ceiling? Or can I start with 1 room, and then eventually work my way to the other rooms?

 

[shetc]

Based on my experience watching Mike Holmes repeatedly fix problems like this, the answer is yes.

He always discusses thermal breaks to isolate the interior from exterior spaces. Since this is a crawl space directly on soil, then you would definitely have a thermal loss happening, more so if the crawl space is not sealed against outside air flow.

Thermal spray foam would be the easiest, but probably not cheapest, way to insulate. It sticks and fills all gaps if applied correctly. Fitting insulation like you have between the floor joists would work as well, but you'll have to stick boards of some sort underneath to hold it in place and ensure there are no gaps.

Awesome, thanks!

 

[Erik the Anglophile]

Thanks, Erik! Insulate the whole crawlspace ceiling? Or can I start with 1 room, and then eventually work my way to the other rooms?

Insulating the whole house definitely won't hurt, you should have it done in a day once you get some material home.
I don't know the climate where you live but having that floor insulated seems like a huge heat sink.

 

[shetc]

Insulating the whole house definitely won't hurt, you should have it done in a day once you get some material home.
I don't know the climate where you live but having that floor insulated seems like a huge heat sink.

It's north Georgia near Atlanta. I would call it a moderate temperature region but definitely feels cold through the floors in the winter. You're right, I just need to get the rockwool, and get on with it. What R value do you recommend?

 

[Erik the Anglophile]

R value depends on thickness. I'd just go with sheets in the same thickness as those 2xsomething beams. Any insulation is better than none and if you live somewhere where you won't get too cold winters you don't need much to feel the difference.

 

[shetc]

R value depends on thickness. I'd just go with sheets in the same thickness as those 2xsomething beams. Any insulation is better than none and if you live somewhere where you won't get too cold winters you don't need much to feel the difference.

Much obliged!

 

[sibelman]

Insulation can be held in place with string - no wood required.

 

[shetc]

Insulation can be held in place with string - no wood required.

I was thinking about those wire thingys, but string would be cheaper.

 

[mac_1103]

Well, those wire thingys are made to hold insulation in pace, so there's that.

The joists are probably 2x10's, so you could go as high as R-30 but R-19 might be good enough for your climate.

 

[shetc]

Well, those wire thingys are made to hold insulation in pace, so there's that.

The joists are probably 2x10's, so you could go as high as R-30 but R-19 might be good enough for your climate.

Thanks!

 

[whoaru99]

I don't know the recommendations offhand for something like that, but be sure to understand if you should have vapor barrier with the insulation and if it should go on the crawlspace side or the house/floor side.

 

[InspectorJon]

The floor is the last place to insulate to reduce heat loss. Heat rises. That’s not to say you shouldn’t insulate, just that the walls and particularly any ceilings above living space are much more important.

If you don’t get much freezing weather you can use unfaced insulation (no paper). If the insulation does have paper the paper should face the heated living space. The “wire things” work great and save time. String doesn’t work well unless you use a lot and fasten it really well to every floor joint. R-19 in mild climate, R-30 in colder. And even colder get more.

I feel like Atlanta has a pretty mild climate. The local building department is usually happy to answer questions like this, given them a call.