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2 Answers
Basement sub-slab insulation

I should know the answer to this already.... I'm in climate zone 6, using the IRC 2009 code. Table N1102.1 requires R-10 insulation below a slab. I've been taking this to mean under the basement floor, but in re-reading it for the 100th time today, I think I've been misunderstanding the requirement. I know it's best practice to insulate under the poured concrete floor in a full basement, but is it required?

In Building Code Questions | Asked By michael maines | May 23 12
2 Answers
Moisture Concerns when Sealing Air Leaks in a Brick and Block House

I'm working on a brick and block constructed house in south east Pennsylvania. The house was built in the 60's and does not have any insulation in the walls. The cross section of the wall consists of 4" of brick, then 4" of block, then 1"x3" furring strips, then drywall. The cavity created by the furring strips basically creates an air chute that runs from the basement to the attic.

In Energy efficiency and durability | Asked By Victor Burgos | May 23 12
5 Answers
Triple-glazed windows and passive solar: Does it make sense to install triple glazing on south-facing windows?

I live in Southern British Columbia, so we are primarily heating area. No air conditioning required. We have excellent southern exposure, and large overhangs on south side. We plan to install triple-glazed windows on N. E. and W. walls, but not sure if triple glazing makes sense on the South side. Will triple glazing limit winter solar gain?

In Energy efficiency and durability | Asked By David Slade | May 21 12
1 Answer
Semi-conditioned space--is this an obsolete term?

I think of semi-conditioned space as within the thermal envelope but is not kept at the same temp as other space. An example would be a attic with insulation at the roof line or an unfinished basement that has minimal HVAC use.

In General questions | Asked By Robert Hronek | May 23 12
2 Answers
Hi, I need to have my windows replaced and eventually new siding.

Which way should go first, get the siding done or replace the windows? Thank you

In General questions | Asked By Holger Herrmann | May 23 12
1 Answer
How can I seal DensGlass (exterior drywall)??

I am using DensGlass on the exterior of my home (urban infill lot with zero clearance). I will be wrapping the exterior with Tyvek. I am thinking of sealing the joints of the DensGlass also. Is this overkill? What should I use to seal the DensGlass?

In Energy efficiency and durability | Asked By Charles Eichenlaub | May 23 12
5 Answers
What is the proper way to flash a deck ledger?

Peter Yost's details show a ledger spaced out from the sheathing and flashing arranged to allow water to flow between the ledger and the building. The July issue of Fine Homebuilding shows a ledger attached tight to the building with a flashing that directs water over the top of the ledger, and potentially on to the joist hangers and the ends of the joists. Does GBA have a preference for one detail or the other?

In General questions | Asked By josef chalat | May 23 12
0 Answers
Venn diagram of detail-oriented insulation-buying groups (any sound nerds here?)

I'm aware that there are other online communities dedicated to sound/acoustics/dampening/soundproofing questions. Nevertheless, I can't help but wonder if GBA has many (any?) regular visitors who focus on (in addition to cutting room-to-room transmission) deadening sound waves within rooms, beyond, say, putting carpets down on hard surfaces.

In General questions | Asked By Minneapolis Disaster, 6B | May 23 12
4 Answers
How do I thicken slab with 2" of foam underneath?

I am building a house on a slab (with in-floor heat). There will be 2" of blueboard underneath the entire slab. I need to thicken the concrete slab16"x8"x10 feet in the center. How do I do this and maintain the continuity of the insulation? Pour the pads first? Cut holes in the blueboard? Help, I start next week!

In Green building techniques | Asked By Charles Eichenlaub | May 22 12
2 Answers
Sill/band-joist: open or closed cell?

I'm planning a DER that includes external polyiso installed down to
the foundation wall, thus covering the sill and band-joist. The
contractor has specified closed-cell sprayfoam on the *inside*
of the sill and joist area to help air-seal and further insulate
that area. The sill is directly on top of the cinderblock wall
without any capillary break that I can discern; it's sufficiently
above grade that most moisture problems that might create
don't seem to be an issue. However, I'm concerned that since
there is invariably a little bit of moisture drive upward from

In Green building techniques | Asked By Hobbit _ | May 21 12
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