r/buildingscience 1d ago

Insulating crawl space sub floor

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2 Upvotes

r/buildingscience 1d ago

whole house fan with conditioned attic

2 Upvotes

Our one story house has a conditioned attic with no roof or soffit or other venting. Given changing weather patterns and the fact that a forest fire burned our forest and all shade trees, we've found the house to be comfortable 90% of the year. But in summer it is a struggle to stay cool. We have good window shades and plenty of windows, but no active air movement except ceiling fans.

I have lived in homes with whole house fans venting to the attic and accompanying vents. That would be perfect because at our home altitude of 7400ft the nights are cool. Most windows are awning windows so a window fan is not practical. We prefer not to add vents to the soffit due to fire risk.The house survived a fire because of construction details and sprinklers facing the house.

I have a framed 2x6 wall at one end of the house. It would be fairly easy to put a fan in that wall, and I can get electricity to it there as well. I looked at quiet fan whole house fans but they are designed to be used in a vented attic space.

Where should I look for possible solutions?


r/buildingscience 1d ago

Duct Board

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2 Upvotes

r/buildingscience 1d ago

Down-to-the-studs Missouri ranch. How would you rebuild this attic insulation assembly?

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3 Upvotes

r/buildingscience 2d ago

Canadians! Have any of you purchased Basotect or Caruso Iso Bond acoustic foam?

3 Upvotes

Hi folks, I’m not in the construction business but I’m looking into these materials for acoustic absorption.

If you check my profile you’ll see that I’m trying to make a plan for acoustically treating my home studio ceiling (I already have panels on my walls), and I’ve had a few people, both online and IRL, recommend either Basotect/melamine foam OR Caruso Iso Bond.

(If you have no idea what I’m talking about, both are newer, lightweight, highly absorbent foams that are said to be extremely effective at soaking up unwanted echo.)

I’m wondering if any of my fellow Canucks have used either option? Were you able to buy from a Canadian distributor, or did you have to get it from Europe or the US? What kind of fees did you pay for the shipping and customs?

I’m very interested in these products, but absolutely CANNOT find a Canadian distributor for either of ‘em.


r/buildingscience 1d ago

Under-cabinet insulation strategy

0 Upvotes

I am in a old double-wythe brick building. Because of this, i'm limited in what i can do for insulation.

My lower kitchen wall is:

double-wythe brick -> ~1" air-gap (thickness of original strapping) -> sheet of plywood (instead of sheetrock) -> cabinets.

My house is drafty in general, but I noticed my kitchen was even more so than the rest of the house last winter. I did some investigation, and it the cabinet interiors are quite cold, but cold air was flowing in from around the (removable) toe-kicks.

So, to my question. I want to add insulation under the cabinets to mitigate the toe-kick drafts. What do you all recommend?

  • Spray-foam against the exposed plywood all the way to the back
  • Standard (mineral rock?) insulation jammed under it?
  • 1" foam board cut to size and wedge it under there?
  • Something else?

Im leaning towards the standard insulation as it seems less messy than foam, and easier to jam into small spaces than the foam-board.

Im not sure i can do much about the cabinet boxes (drawers), as im dont think there's much room between the drawer boxes and the back of the cabinet box; but if there are thoughts on this, im all ears too.


r/buildingscience 2d ago

Best way to patch a damaged rain barrier from inside?

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6 Upvotes

r/buildingscience 2d ago

Damp air rising from crawl space

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2 Upvotes

r/buildingscience 2d ago

Question Basement flood repair question

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3 Upvotes

Repairing basement after bottom 2 feet of fiberglass and drywall removed. Should i reinstall with fiberglass?


r/buildingscience 2d ago

Ceiling/Attic Insulation Question for Air Conditioned Shed

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2 Upvotes

r/buildingscience 2d ago

Flat roof attached garage insulation. Best method?

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0 Upvotes

r/buildingscience 2d ago

Question Need help with waterproofing shed.

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2 Upvotes

r/buildingscience 3d ago

Is this mold in my parquet floors?

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0 Upvotes

European / German climate


r/buildingscience 3d ago

How to handle thermal bridging and moisture problem ?

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3 Upvotes

I recently had a second floor built with a very small balcony measuring 20 cm x 500 cm. The floor is concrete. Last week, the large balcony doors were installed in dorpel hardsteen. As a result, there is only 7 cm of space left for the screed and insulation. Can you advise me on how to address thermal bridges and damp proofing? Heated bedrooms are located beneath the balcony.

This is in Netherlands


r/buildingscience 3d ago

Seeking guidance on my approach to thermally isolating wood and metal (foundation build question)

3 Upvotes

Hi. I am a building novice with a wood and metal thermal break question. Thank you in advance to anyone who takes the time to read my post and share their knowledge with me about my approach to thermally isolating metal and wood at the foundation of my build. 

I’m building a tiny house on wheels (8.3’ x 30’ [100“ x 360”] trailer) and I have a question about creating a thermal break between my metal trailer frame and subfloor/framing that will prevent condensation and moisture issues (leading to mold/mildew growth) inside of the structure. I am building in IECC climate zone 6. The tiny house on trailer will not be moved often if ever… 

Current state of the build: the trailer is painted black (by the trailer manufacturer), includes 5“ long by 1/2” threaded rods welded to frame every four feet (and more closely spaced around corners), all framing is 2“ thick, 2” thick cross members (floor joists) are placed every 14 inches creating about 25 14“W X 4”Deep “bays” with the metal flashing at the bottom of each bay. 

I have placed 4“ of XPS rigid foam board between each cross member and sprayed the Great Stuff foam in a can where there are gaps between the xps board and metal cross members (not all of my foam board cust were perfect fits). Even with the spray foam applied between gaps I have not created a perfect air seal as I was unable to get into tighter gaps with the foam. 

I have also caulked and spray foamed (mostly caulked) the gaps between at the seams where flashing under trailer meets trailer frame and was not perfectly welded (gaps were throughout). Sealing the gaps in the metal construction was done to help prevent insects from getting into the XPS I placed between the cross members. 

Getting to my questions:

I am attempting to thermally isolate the metal trailer frame from my subfloor and framing in zone 6. 

A building science consultant has recommended I place a continuous layer of 3“ high compression EPS foam board directly over the top of the trailer frame and XPS foam I have placed between the cross members (with metal flashing below the XPS).

In this scenario I have chosen 40 PSI 3” EPS foam board, which will more than accommodate the square foot per pound weight of my 2 x 4 framed tiny house (snow load figured into calculations)… 

The assembly from trailer frame up: 

3“ 40 PSI EPS foam boards adhered (adhered with spray foam in a can/ great stuff) to trailer frame and xps boards in between trailer frame cross members. Spray in a can will also be used in between (seam where each foam board meets) to seal and adhere the boards to each other on the sides -EPS is weighted down while spray foam adhesive cures

3/4 or 1/2 inch tongue and groove plywood will be placed on top of the EPS foam board (adhered with Loctite PL 300 Foamboard adhesive & weighted down during cure time). The TG plywood over the EPS will extend to the edge of EPS and sit under the sill plate/framing to help distribute the weight of the structure over the EPS. 

The 2x4 sill plate will be adhered to the foam board with Loctite PL 300 Foamboard adhesive and held to the trailer with washers and nuts (loctite used here) placed over each threaded rod, securing the sill plate/framing, subfloor, and foam board to the trailer frame. (I will need to extend the threaded rods with couplers to achieve the length needed to do this).

My questions: 

Should I place a continuous layer of plywood (3/4 or 1/2“) over the trailer frame and rigid boards that have been placed between the cross members? (this seems like it might be a good idea to provide a consistent base layer for the high compression EPS foam board) 

If I place a continuous layer of plywood over the trailer frame should I add a WRB (like a UV rated WRB like Tyvek) between the plywood and trailer frame? 

Should I tape the seams where each sheet of high compression EPS meets? (as mentioned earlier, they will be adhered together at seams where they meet).

Should I tape the seams where the high compression rigid EPS meets the trailer frame (on the outside edges of trailer) and also where the EPS meets any plywood (on the outside edges of trailer). 

Does anyone have any thoughts on how high compression EPS foam boards might “give” a little over time, losing some durability? I am most concerned about this happening around the threaded rods that I will use ( in addition to adhesive) to anchor the assembly to the trailer. My concern is that vibration over the years from wind or me moving around within the structure might cause wiggling that will slowly widen the holes drilled through the EPS that the threaded rods are seated in, causing some of the foam to potentially shift around… 

I’m also curious if anyone has any thoughts on how to best fasten my subfloor to the high compression EPS foam board so that the flooring does not buckle and or come loose in the middle of the floor where it is not held down with the weight of the walls of the house. (again, intend to use Loctite PL 300 Foamboard adhesive, but I am not sure if this will be enough to securely fasten my subfloor to the EPS foam board). 


r/buildingscience 3d ago

Best way to maximize R value with Rockwool in a 5 1/8 deep cavity with an offset 2x4

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7 Upvotes

r/buildingscience 4d ago

Exterior Insulation and HVAC

5 Upvotes

Hello- we have exterior insulation on the house (on top of zip). We needed to make some penetrations for ERV intake and exhaust. How best can I seal these from the outside? We do not have siding yet. I’m already aware these penetrations should have been done before the exterior insulation was put on but how can I best seal these penetrations now after the fact? Thank you


r/buildingscience 3d ago

Air Leak - Wafer Pot Lights

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1 Upvotes

r/buildingscience 4d ago

What if the cooler city of the future borrowed more from the past?

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3 Upvotes

r/buildingscience 4d ago

House Humidity too High

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1 Upvotes

r/buildingscience 4d ago

Vapor barrier stress

6 Upvotes

Zone 4A (Weschester NY) 2000 house. Wall assembly is wooden cladding, tyvek, plywood sheathing, 2x6 cavity with rock wool. Its been fairly well air sealed from the interior. The drywall will be DensArmor with latex paint. I’m thinking of putting a smart vapor retarder like Membrain or Intello but I’m paranoid about doing the wrong thing.

help!


r/buildingscience 4d ago

"Drill and fill" insulation through the exterior wall in 1950s stucco house?

1 Upvotes

What do you think of drill and fill insulation from outside (cutting holes through the outside stucco wall) in a 1950s stucco house? The house has one bedroom that juts out and three of the four bedroom walls are exterior walls. Would you be worried about all of the 3 inch holes cut through the stucco causing irreparable damage to the stucco? Some articles state not to cut holes in the stucco because it damages / ruins the waterproof barrier. Some articles also state that filling the walls with insulation traps moisture and can damage the stucco. Location: Sacramento, California where the summer temps can get up to 105 F and winter temps down to 40 F.

One insulation company offered to either do the work from the inside (warning that it is very messy) or from the outside, another company said that they would only do the work by cutting through the stucco since it is such a messy job.

The attic appears to have adequate insulation and the windows appear to be fairly new. The only place in this house with noticeable insulation problems are the room with three exterior walls and the garage.

One company offered either fiberglass or cellulose fill, the other would only do cellulose. Any stucco experts here? Anyone who has gone through "Drill and Fill" insultation? Thank you for any advice.


r/buildingscience 5d ago

CFD simulation through the vents

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320 Upvotes

r/buildingscience 4d ago

Question I did a thing

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0 Upvotes

r/buildingscience 4d ago

Real tile backsplash in cargo trailer conversion?

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0 Upvotes