A Tale of Two Rooftops

The snow on my rooftop is melting much more slowly than that on on the other houses, since my house keeps the heat in! And, note the beautiful new siding!

Dr. Warm and Lascaux

Okay, so now we were ready for really foaming the basement. We loved the young earnest guys sent by the bigger insulation company, but we needed someone who really got it about the building science. We found Dr. Warm (whose real name is Robert Jordan). Here he is testing the Cedar Breather to see if he could get it to not stick entirely to the foundation when the closed cell foam hit it. The idea was to create a drainage plain. He developed a spraying style that was kind of at an angle. It worked.

Testing the Cedar Breather

The "angle" style spray

More"angle" style

Spraying the first coat of the closed cell foam. This is one thing I don't think too many people would enjoy doing. But Dr. Warm loves it!

The foam is done--all 3"-plus of it

Dr. Warm's work made Liane think of the prehistoric caves of Lascaux. After we put the thermal barrier (15 minute fire protection) on the basement walls, we will consider getting some murals painted...

Guinness, Liane's long-haired Dachsund, would definitely like to be depicted on the wall

The basement stair walls were protected and fire-blocked with conventional sheetrock. The open cell in the ceiling will get the thermal barrier paint.

Inside Foam Job cont’d

When we decided to foam the basement walls, we had to make a decision about whether to put in a perimeter drain. Liane’s basement is generally fairly dry (except when there’s a plumbing leak). But in this era of climate change, extreme weather, and biblical floods–even in Somerville–we decided that the responsible thing was indeed to install a perimeter drain. We would connect it to the foundation walls by means of a drainage mat which could send any moisture coming through the walls–down along the perimeter drain. A pump in a sump at the low end of the basement could pump any accumulated water out if necessary (whatever its source). So that’s what we did.

The diamond blade that cut along the perimeter of the basement

Diamond saw marks

A little (actually a lot) of drilling

Abi putting up the Cedar Breather, which actually worked as a more affordable approach to a drainage mat.

Rick and Abi with the Cedar Breather--and note that the electrical panel has been moved inward temporarily

Laying out the filter fabric wrapped, perimeter drain line which was installed deeper than what is shown here. Btw, the foundation walls are fieldstone with brick above.

Concrete covering the perimeter drain. Yes, we had to go around the Pheonix because of the switch in how to deal with the basement.

We did decide to cover the basement windows and to later foam over them. Liane only uses her basement for storage and the building systems. If she wants to have windows in her basement at a later time, they can always be cut out through the rigid and the spray foam from the outside.

and there's the sump...

No, we haven’t seen any closed cell foam in the basement yet–but it’s coming in the next post. Just wanted to let you know what we needed to do before we could foam. Dealing with moisture is probably one of the most important things in any retrofit–deep or not.

Inside Foam Job–the Attic

In all fairness to the foaming guys, the HVAC fellows took a while, so the inside foaming also took a while to get started.  We had to get the HRV supply runs done in the attic for the 3rd floor apartment, before we could foam the rafters.

Foaming guy for the open cell spray foam at the attic and dormer rafters

HRV return run exhausting from the 3rd floor bathroom (supply runs are at the furthest ends, for good air mixing)

After foam job in attic--buckets were to protect vents yet to be connected

Interior view of air bypass where sidewalls meet rafters

Yes, had we been a bit better coordinated, we would have sequenced the cellulose between the attic joists after the spray foam at the rafters.  As it was, we just did the best we could from the exterior, as shown in the previous post.

Openings at roof sheathing 'before'

Another thing we would have done, and can still do, is to acoustically seal the ducts venting through the attic to the outside. Right now the big one (where a number of vents are gathered) acts like a trumpet, and Liane can hear music heralding community events such as 5K races–through her stove hood!

‘Trumpet’ inadvertently created by the venting

Air By-Passes…

Ambrose, one of our DER gurus checking out the sidewall for bypasses

While you’ve got to have good air for your human lungs to breathe in a house, you don’t want to have uncontrolled holes letting air in and out, and giving an easy ride for lots of heat to exit and enter.  Air by-passes, thermal bridging and moisture penetration are anathema to a deep energy retrofit.  You’d think that with a superinsulated retrofit, we wouldn’t have an air bypass problem, but we did—because of the structure of the house. The rafters were sitting on 2×10′s laid flat across joists that protrude outboard from the sidewalls like the fins on a motorcycle engine (wierd metaphor, but that’s what they reminded me of).  Needless to say–a “chainsaw” retrofit–to keep a continuous air and water plane, became out of the question.

Joists above the southeast sidewall

Rafters and joists with structural plate in between

"Motorcycle fin" joists above southeast sidewall

"Crenellating" the rigid foam around each joist--2 layers worth...

Yes, we could have boxed everything in–but that didn’t happen. Instead, we spray-foamed the ____ out of all the air-bypasses at the joists (at least I hope we did…). And then used some nano-paint to try to “assuage” the conductive heat loss. I’m not sure the strategy really worked. An infrared scan will let us know soon enough.

Spray foam (closed cell) at the soffit joists

Nanopaint at joists but not at "joist-tails" that are just extending the roof eaves visually.

How we might have dealt with air bypasses and thermal bridging from the inside--if the attic sprayfoam had gone according to plan--see next post...