Fire retardant paint and fire safety

I ordered an intumescent paint additive which adds fire retardance to any latex paint, mixed it into a can of white primer, and gave it a quick test. It works!

The stormboard on the left was painted with plain latex primer. The stormboard on the right was painted with the same primer, with an additive called Flame Stop III mixed in. They were both exposed to a candle flame. The untreated board is shown after 90 seconds, when it ignited and sustained flame. The treated board is shown after 180 seconds, and still hasn't ignited.

Intumescent coatings work by forming a foam at high temperature. In a thick industrial coating, the foam would be inches thick and really fireproof the structure. In a thin paint the defense is minimal but significant.

We'll use this primer in the kitchen, behind all the appliances and cabinets.

Other fire-safety measures include backing the refrigerator, dishwasher, and stove cavities with rock wool, and wrapping bathroom fans with UL94-V0 nitrile foam. These materials are all good sound absorbers, as well as fire retardant.

Then there's all the building-code measures, like sealing floor penetrations with fire retardant caulk and foam, hardwired smoke detectors, egress codes, etc.

Attic radiant barrier installed

The outer half of the radiant barrier was installed today in the attic - all that shiny aluminized housewrap. The early returns suggest that it works: air temperature got up to 83 degrees today, shingle temperature reached 135 degrees, but the attic temperature didn't get above 85. The attic is still completely open to the rest of the house, until the walls are built, so it's absorbing all the heat load from the house as well as solar.

The rest of the barrier goes right under the drywall. I'm going to leave the lower half (cripple walls) unfaced, to avoid more interference with wireless signals. So far both cellular and wlan signals seem to be unaffected.

New gas line

Our new gas line was installed today. We thought they would reuse the existing line, perhaps with a new sleeve, but instead they trenched a new line to a new location across the street. The trench was actually subterranean, made by a "trenchless impact borer", which looks like a 4" torpedo with a hydraulic line.

I warned them they didn't want to dig 4 feet down in our previously excavated sand, but they don't seem to listen to homeowners. Didn't lose the utility pole, they just had to go wider than expected.

That black thing on the wall above the gas pipe is actually the chimney for the new house. With no fireplace the only exhaust is from the gas boiler, and since it's condensing, the exhaust temperature and waste products are minimal.

New water line

Our new water line, 1" shiny copper, was installed on Saturday. Michael Shea did the excavation, Newton public works did the plumbing. The water meter will be installed Thursday - I requested it three weeks ago as soon as we got the installation schedule. Until then, we have unmetered access to Boston's finest Quabbin Gold.

Catching the breeze

Finally a nice spring day and I can open some windows. Working on the first floor with a window open at each corner of the house (plus the front door) is remarkably pleasant. The breeze flows through the house, and it feels like there must be an ocean view somewhere near.

Icynene foam insulation

Anderson Insulation insulated the attic with Icynene foam today. Very cool stuff: here's a quick movie of the fellow who spent about an hour spraying the attic, followed by before and after pictures of the attic peak.

Sewer connection, day 1

We're running a whole new sewer pipe from the house to the street. The City of Newton usually requires this if you renovate more than 50% of a residence. Frankly, though, we really needed a new line - the 60 year old ceramic pipe had been compromised by roots, and couldn't run straight to the house since we moved 6 feet south.


Michael Shea and Company is doing the excavation, and will also do the water line on Saturday, and landscaping later on. Here's the crew after they'd opened the street and located the sewer main near the old connection.

The surprise was that the sewer main was 11 feet down, although in the "upstream" manhole it was only 5 feet. The main drops low under the aqueduct near us, but we thought the drop was downstream.

You can see our old sewer line running to that brick "chimney", then down to the deep main. The big shallow pipes are storm drains.

The plan was to replicate exactly that structure, but with PVC pipe embedded in concrete instead of ceramic and brick.

The result: the old connection has been capped, and the new one is complete and tied in a few feet downstream.

Then the whole street opening is filled with weak concrete, and plated over for the night while it sets. Newton Engineering insists they are going to require this of everybody this year, even though it adds 50% to the cost of any utility improvements. We kept about half of the perfectly good sand/gravel mix, to replace subsoil on our lot.

Cathedral ceiling insulation

The Icynene insulation is too expensive to use everywhere, so it's only on the roof and everywhere else in the house has fiberglass insulation. In this picture of the attic you see where the untrimmed Icynene is used for maximum insulation value, fiberglass for economy, and trimmed Icynene where the cathedral ceiling is.

No, it's not much of a Cathedral, that's the term of art for a room's ceiling that is also an exterior wall, and it's always an insulation challenge. In this case, that part of the roof is framed with 2x6 rafters, so there's really not enough insulation between us and the 160-degree roof shingles baking in the summer sun (the roof design is unvented).

The plan is to implement what I call a double radiant barrier below the Icynene. The Icynene will be covered with perforated aluminum foil (actually an aluminized housewrap-like product called RadiantGuard). Then 1" strapping will be applied, then another layer of non-perforated foil underneath the sheetrock. The two foil surfaces have high reflectivity and low emissivity - they reflect radiant heat, and they don't radiate the heat they absorb. This is the same principle as a Thermos bottle, except that the surfaces are separated by air not vacuum.

It's hard to translate the potential benefit of this insulation approach to conventional metrics. Some analyses suggest that a single radiant barrier makes an R20 wall perform like an R30 wall, which is about what we're hoping for. We'll be able to measure the surface temperatures on the foam versus the drywall, and get a sense of its performance.

Addendum: performance measurements in warm weather

Street open tomorrow

Sewer pipe will be installed Thursday and Friday. Water pipe will be installed Saturday, and street patched on Monday. Gas will be installed next week (small hole on other side of street), as will electric (overhead).

These one-day jobs each take two days because we're required to fill the street with concrete afterward, and it has to set overnight. 47 yards of concrete at $80 per, adding about $5000 to the job for no good reason at all. If the fill under the street is anything like our soil (class 1 sand/gravel) we'll use it for subsoil.

Moving day May 30

We've signed up the Gentle Giants to move us back in on May 30.

Plumbing, electrical, heat, utilities are all on track to be done this month, so the house will be essentially functional May 1. First two weeks in May will be finish work on floors (tile), walls (sheetrock patching), and trim.

Electrical status

The electrician wired the attic today, and successfully dropped the module "D" lines down their conduits to the basement. Here's the resulting rats nest...

Before and After

The exterior carpentry is essentially complete, so not much is changing outwardly these days. Here's a picture of the old house, then current for comparison. (Recall that the new house is 6 feet further south.)

Utilities schedule

KeySpan called me on Friday to ask when we wanted the gas line
installed.

I was momentarily stunned, but recovered quickly, and asked them
to come the week of April 23, after the sewer line is in. They
have their permit application in and will confirm the actual date
next week.

So the current plan is:

sewer: week of 4/16 (will confirm with Shea today)
water: 4/21
electrical: week of 4/23
gas: week of 4/23
water meter: ?

Plumbing progress

Plumbers have been working this week, and should have the water system ready to test today. The big issue has been some of the drain piping that didn't conform to code and had to be reworked. For example, on another MSI house on Chestnut St, the drain lines used normal 90-degree elbows, but our code calls for large-radius elbows. So our plumbing inspector had us take out three ceilings to look for the same problem. In this case, MSI did use large-radius elbows, so there's no problem - except for the cost of repairing the ceiling, which we'll have to argue about.

Plumbers will move on to hydronic heating system next week, and the electrician will be in to finish wiring. We'll get our water pipe on April 21, then we can get electrical service.

All in all, we're looking good, and the only schedule uncertainty is the gas line.

Broken webcam

Sorry the webcam's been out. I've been sick and don't want to infect our elderly neighbors by visitting to fix it.