[Greenbuilding] insulating beneath an existing floor.

[John Salmen]

Sounds beautiful.  I would also consider or briefly look at what isolating the crawlspace from the ‘conditioned’ space would mean for freeze/thaw on the lime mortared stone. Should be fine as lime is more forgiving and as you say it works for barns. Have they been repointed with cement at all? 

 

Well passiv type walls means a passiv type floor – r30-50. I would go eps foam board laboriously cut to fit and sealed (6-10”).  Its your moisture barrier but still can take in moisture and releases it – generally in decent moisture balance with the wood its in contact with (depending on dimension). Downside is the occasional critter chewing in but they have to live somewhere and generally find somewhere better. The alternative is rockwool even more laboriously cut and fitted and patched in and then supported but still subsequently falling out as it loses its rigidity or critters push it aside – plus the folmaldehyde.

 

Spray foam ....possibly....but be careful on that one lots of problems on improperly proportioned mixes...

 

Ventilation of the space especially if spray foamed.

 

From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of Sacie Lambertson
Sent: July-29-15 8:59 PM
To: Greenbuilding
Subject: [Greenbuilding] insulating beneath an existing floor.

 

What is the best way to insulate the floors of an old house that sits on a 30 inch limestone foundation wall?  The wall, solid since 1883, needs to continue to 'breathe'.  Limestone such as is used for the foundation is similar to that used in old barns; the stone will last a very long time as long as it does not have dirt behind it, ie as long as it is free standing.  We've had personal experience with this when we used old barn foundation stone to build rock walls behind which is dirt.  They began to deteriorate relatively fast.  

 

Most of the interior of the old house will be nearly gutted, leaving only the the exterior siding, which is also original amazingly enough, as is essentially the interior.  The old yellow pine floors will be retained but must be insulated underneath.

 

The house will be reconstructed with double passiv haus type walls.

 

Thanks for your advice,  Sacie

 

 

 

 

 

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