December 6 is the fourth monthly weatherization barnraising HEET (Home Energy Efficiency Team), a Cambridge, MA energy coop, has done. About 40 people have shown up to each one, some from neighboring towns who are planning to do it themselves. Weatherization barnraisings make an immediate difference and, if they went national, could become grassroots green job training for some of those 2.5 million jobs Obama is planning.
This barnraising will be done as part of Energy Smackdown, a reality TV show, for their air sealing episode. They will use a blower door and infrared camera to get data about a house, the Cambridge Smackdown team will have 4 hours to seal the house as well as possible, and then they'll use the blower door again to figure out how much the sealing helped. THEY ARE INVITING HEET TO COME AND HELP.
There will be well-known energy experts on site and a blower door and infrared camera in action. We will seal a home and then get real data on how much our efforts helped.
If you want to learn about weatherization from top-rate people, come to this event.
December 6, 2008
SATURDAY 8 am - 2 pm
100 Henry Street
Cambridge, MA
Contact: Audrey@AudreySchulman.com
http://maps.google.com/...
NOTE: If too many people turn up, then people living in Cambridge get to be on the team first.
For those who want to learn technical details about how to air-seal a house, here are some informative emails from Kerry, one of the team guides for the Smackdown. They describe what to look for.
Hi Patty,
I am currently working on supervising the preliminary air-sealing challenge in Arlington. I visited the home to be sealed on Saturday and the home owner and I came up with a pretty good list of things to do and photograph. I’ll add that below. Saturday December 6th is a possibility for me to supervise your event. I suggest 8am or so to whenever it is complete. Let me know if this is OK.
At the day of the event I intend to meet the crew and take a quick tour of the house with that crew. I can point out the areas of air-sealing interest before the event. I then take a pre-challenge air leakage reading and start the 4 hour timer.
Here’s the areas of interest and why:
The stack effect in buildings contributes to a great deal of energy (heat) loss. A leaky house has a pretty efficient air flow cycle, “the stack effect”, where warm air rises to the attic and exits through holes while cool, outdoor air enters through the basement holes. Warm air rises to the highest point in a house due to its greater buoyancy and lesser density. This buoyant, warm air exerts a positive pressure at the roof area. It actually is trying to escape under positive pressure, blowing out. If holes allow it to escape the basement will be under negative pressure sucking in outdoor air. Although any hole in the house will let the heat out by way of convection, the transfer energy from higher concentration to a lower concentration, hot to cold, the stack effect is more efficient due to the pressures involved.
So, all leaks result in energy loss. The priority leaks are in the basement and the attic, though. Note that the blower door doesn’t show priority. A hole is a hole under -50 Pascals of pressure. Under natural pressure we find the priority.
Key things to look for. This list is in no way complete, but a good start:
Basement-
Many auditors like to call the basement ceiling the insulation and air sealing plane. Most air-sealers don’t agree. It is very difficult to get an effective air seal at the floor plane because of limited access and number of holes. There are also many pipes and heating equipment that work the best in a warmer space. We always insulate and air-seal the basement walls and leave the basement within the thermal boundary.
If, for some reason, a group decides to tackle the basement ceiling for air-sealing, it must not have plaster on it or there will be no access. All wire and pipe holes will need to be foamed or caulked and checked with a smoke stick. The perimeter of the chimney is typically leaky because code requires a 2” clearance from the chimney to a combustible material. The only thing to do is to stuff it tightly with mineral wool insulation.
My recommendations (walls as thermal boundary):
Windows and doors should be weather-stripped and latched. Most old, wood windows have no weather stripping and don’t shut or open very well. I think the windows could be caulked shut if they are never opened. If they are to remain operable, foam tape could be applied to the window stops. I recommend Q-lon weather stripping mounted to wood carriers for doors. EFI #3540.18 (white kit). Door sweeps are necessary and either attach to the bottom of the door or to the face. The best ones cover the full bottom of the door, but often require the door bottom to be trimmed. Either door sweep will allow air to leak at each end if a beveled foam gasket is not applied at the bottom of the jamb. You see these on new doors, but rarely on old ones. They are not commonly available, but a typical window / door sales business could get them.
The wood framing connection to the foundation is a large leak source. In older homes there was no gasket between the two materials. Sometimes you will see cement curbed against the sill as an attempt at gap filling. The connection of the floor and wall framing to that wooden sill also are leak sources (by way of leaky exterior sheathing). The most effective and quickest way to seal the whole assembly is with the two-part spray foam from EFI. If the whole assembly is exposed, (no plaster ceiling), I would spray the whole area with a200 board foot kit #3530.405. I know this bigger kit is $300 and out of budget. We only had a small amount of area at John Peach’s house so we ordered the 15 board foot kit #3530.19. Perhaps when labor is free several tubes of caulk applied to the joints only would do a good job.
If a house has a stone foundation any holes and cracks in it are air leaks. One part foam cans could be used, but the two part is stickier.
If a house has a concrete block foundation, the hollow blocks can be a problem. Holes in the face should be filled. Sometimes the hollow cores are exposed at the top where the sill attaches. These holes need to be stuffed with something like fiberglass insulation as a backer for spray foam. Again, two part foam is the best, but perhaps not mandatory. Maybe 1 part will work.
Note- All foam should be very warm before using it. 70 degrees is an absolute minimum for two part foam. The warmer the better.
Attics-
The thermal and air boundary in most houses is the attic floor. One can make a pretty effective air-seal from the attic if the insulation is not covered with wood for flooring. Air-sealing products here are spray foam, caulk, fire-stop caulking, mineral wool, foam gaskets, 1” rigid foam pieces, drywall pieces, foil tape. Q-lon and door sweep for regular doors.
Areas of concern:
Attic access. Pull down stairs are very gappy. The most effective seal is by way of a cover that get strapped down and gasketted to the floor. EFI sells a couple of varieties. A second rate seal is made mad using foam tape on a pull down stair or foam tape and eye-hooks to seal a plywood ceiling access.
Chimney. Need to maintain a 2” clearance to combustibles. Sometimes there is none already. Use an intumescent, fire-stop caulking for small gaps and stuff mineral wool tightly into larger gaps. Metal flashing or gypsum board can be used against the chimney, but this is an advanced technique used in some instances.
Main 4” plumbing stack. Typically there is a large gap around this. Stuff fiberglass insulation into the gap as a backer for spray foam.
Wall plates. You can often see the top, 2x4 plates of the framed partition walls below. Any where you see wood butted edge to edge with other wood or to plaster it will need to be foamed or caulked. All wire and pipe holes need to be filled with foam or caulk.
Perimeter walls. Houses with insulated attic floors usually have vented soffits. If the air coming into the soffits can get to the top plate of the exterior wall it will likely infiltrate. It is important to seal the interior edge of that top plate to the adjacent plaster / drywall of the ceiling below. Otherwise, cold air typically gets into the rooms below through cracks or behind crown molding. Note: this outside air can also get into exterior walls, but well insulated walls are the solution. Gable end wall top plates need to be sealed, too, like interior partition walls.
Recessed lights – Factory Air-sealed recessed lights should be foamed to the ceiling plaster. Non-airsealed lights should have rigid foam, or drywall, boxes made to cover them. Seal the corners of the boxes with spray foam and seal the boxes to the ceiling plaster with spray foam. The lights should not physically touch the boxes as it could be a fire hazard.
Bathroom fans- seal the fan box to the ceiling plaster with foam. Seal all holes in the fan box with foil tape caulk or foam. Note: It is important that the fan duct be routed directly outside. It can never exhaust into the attic.
Heating cooling ducts- Spray foam vent boxes to the ceiling plaster.
Middle of house:
Sources of leaks:
Windows – weight pockets, perimeter of sashes. Weather stripping windows is fairly advanced. We can apply rope putty to leaky seams for the challenge.
Doors- Q-lon, door sweeps, corner foam wedges.
trim- caulk baseboard to floor and to wall. Caulk crown moulding to ceiling and wall.
Electrical. Install trim plate gaskets to switches and outlets.
**************
Patty,
The day and time is fine. Photos sent to me would be great. Here’s a longish list. * means priority. Written descriptions of others would be fine.:
*Exterior shot of the house to gauge overall style and size. More than one side if it seems appropriate.
*Exterior shot of the soffit are of the roof. I am looking for soffit vents if they exist.
Basement:
wall to see type of foundation and condition.
*connection of wood framing to foundation. I am looking for an overall assembly shot.
where a chimney goes through the first floor.
where the main plumbing waste stack goes through the first floor.
window.
exterior door.
Attic:
*access hatch, attic side and finished side.
*chimney perimeter
plumbing pipe area.
*Soffit area.
Interior photo showing a window.
Overall length and width of house would be helpful.
Kerry
The Home Energy Efficiency Team (HEET) is a Cambridge-based
co-op bringing neighbors together to weatherize our homes
and take the energy future into our own hands.
PS: The same day is the Roxbury Energy Fair in Boston from 10 am to 2 pm at
Twelfth Baptist Church
150 Warren Street
Roxbury, MA
Sponsored by ACORN, Boston Climate Action Network, and the Twelfth Baptist Church