Expert: Dan Griffin - 6/24/2011

Question
QUESTION: I might be buying a bungalow in Rockaway,NY. It needs all new windows(5). The building has no foundation, it's built on a wooden frame, not a frame to speak of. When I install the windows, I'm pretty sure there's no insulation in the outer walls and nothing under the plywood floor either. I know the attic is just framed no insulation at all and the attic floor is just 2/4. What's the best way to insulate this place? I mean house wrap, insulaion sheets,1/2,3/4, outside walls? No rush Dan pretty massive query!! Thanks in Advance!

ANSWER: John, this sounds unusual - was this a summer shack or similar?  There must be some form of foundation as wood sitting directly on the ground would be rotted and mostly gone.  You may mean that it does not have a continuous concrete stem wall on which the house sits.  You may well want to consider creating  some barrier if this is just open air.  Again, it seeems unusual that this resort type area would have something that had never been upgraded through the years.

As to insulation - foams provide the maximum impact per inch.  These can be in rigid sheets or spray applied.  The sprayed or injected product will help create a weather/vapor seal in addition to insulating and wouild be worth looking into subject to available contractors, cost, etc.

If you intend an entire new floor, you could cap the existing with rigid high density foam board and cap with plywood and finish flooring.  The other option would be to insulate the joist chambers below.  Here again, spray foam would be most effective subject to access.  If the foam will be exposed you will neeed to create some type of exterior surface to prevent rodent and insect infiltration.

You don't give any dimensions, but 2x4 rafters and celing joists imply small.  If the ceilings are in good condition, your best value in the attic will be blow in insulation.  If the spans cannot support the weight, you may need to increase the load bearing capacity of the existing framing.

If the exterior is in sad condition you might price having the place insulated with multi-inch ( 1 - 6 inch) foam board sheets covered with EIFS.  YOu would end up with a new exterior, good insulation, and a custom style.  Make sure to understand drainage planes and vapor barriers before heading this way.

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QUESTION: Thanks Dan! Good guess, a summer bungalow. That's one reason why no insulation I guess. Throw a boiler in and rent year round. You're also right not really a frame, just a few spread out cinderblocks with a stick of wood here and there. I've been crawling around under these 4 shacks for close to 30 years installing heat and new plumbing. The dimensions are 8' high, not counting the roof and about 40' deep from the front and I guess around 30' wide. The place has vinyl siding on 3/4 plywood. I figure it might be easier to insulate from the exterior and add new siding since it needs a front door and 5 new windows. I see most new houses now are wrapped in that vinyl looking wrap. The inside floors are 3/4 ply also. I figure I could insulate between the 2x4s or 2x6s. I did figure to nail 2x6s on the 2x4s in the attic for better holding up the roof and to give me room for decent size fiberglass ins. Just to show how the frames are one of the bungalows sank into the sand these places are built on, the sand came up in the rear so they took about 4' off the rear and closed it in. These places seem to sink or rise. One of the owners hired a crew that came in with about 3 trucks and a bunch of labor and raised the house using jacks and built a cinder block foundation and dropped the house right on it. He charged about 30,000 bucks. A different owner had a small crew come in and dig around the place and pour some cement around the perimeter and just gerry rig the walls to sit on the cement.As you can see this could turn out to be a big question. If you like maybe I could thank you profusely here and send you some cash for answering all these insulation questions. Thanks so much Dan! You really seem to know your insulations parameters!

ANSWER: John, I think I would still spend the time and/or money on a good foundation.  Anything you do the place will increase the weight and if things are shifting or settling now, it can only get worse.  It may be as simple as crating bearing pads around the building that will allow you to jack the structure and set something like solid CMU masonry units.

I wish you good luck in your venture.

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QUESTION: Thanks Dan! I thought I scared you away, LOL! What are crating bearing pads? Should I leave you alone and just google that? Also CMU?? Are you interested in helping me with advice as I slowly move forward?

Answer
john, Sorry, I get to thinking everyone can read my mind.  CMU = Concret Masonry Units = cement blocks.  I was thinking about stacking solids in the flat.  They come in several thicknesses depending on local manufacturer - typically 3 5/8", 2 1/2", 1 5/8"


C_R_E_A_T_I_N_G  bearing pads.  Foundations are supposed to go to frost depth-you would need to contact your local AHJ (authority having jurisdiction),in other words, the local building department  and code enforcement office.  I fear that your geographic area will be close to 4' deep to get below frost depth.  The size of any footing is dependent on the bearing capacity of the soil ( a swamp won't hold up what a granite outcropping will).  The ultimate answer needs the weight of the structure and the bearing capacity of the soil.  There must be enough square inches to carry the loads imposed.  Your frost depth may give you some reasons for the high cost one of your neighbors had.

Feel free to continue to ask questions.  Sometimes my work schedule and, recently, my computer problems may cause a small delay in response time.