I am renting a house on Vancouver Island, and upon moving in noticed moss on the roof every where and asked if they had the attic inspected for mold and was assured no sign.

Well, noticed immediate moisture issues such as condensation and repeated returning mould along window pane; I have to consistently run the dehumidifier and empty it out at least 4 times a week (I don’t think that’s normal), and if it fills while asleep the RH will get up passed 80%.

My family is experiencing health issues such as rash, itching, headaches, sinus congestion and subsequent infections just to name a few which have all been ruled out as being anything else from the doctor.

Peeked up in the attic and found this - clear abnormal discolouration from adjacent sheathing on one pane as well as suspected other areas (I didn’t go all the way up).

Based on this rudimentary evidence what are your opinions?

UPDATE: newer-ish post https://www.reddit.com/r/buildingscience/comments/1qsnpuk/i_went_up_again/

Anyways, I figured out what was going on. So the way it’s set up is the bathroom and said vent is adjacent to the attic entrance which is not fully sealed. As I run the dehumidifier which is right around the corner centrally, it is pulling that air from the attic. When the bathroom vent is on and door is open it is basically creating a giant loop of mouldy airflow. 

Landlord has an appraiser coming soon so we shall see. Meanwhile I am at a hotel and feel better. Thank you all for your insights!

Hey everyone, I posted in this group 4 months ago showing you all this weekend side project that would convert any complicated 2D detail into 3D: https://www.reddit.com/r/buildingscience/comments/1p4s442/fun_side_project_drop_your_detailshop_drawing_in/

Fast forward, the response to the tool was amazing. I had over 3000 people try it! There was a lot of learning in that process but the most often way contractors wanted to use it was to help understand plans when estimating.

So now I’ve created something new, by using the latest AI that is basically an all around assistant to help contractors with estimating and managing construction projects. The newest AI will sift through every page of plans an extreme detail. It will help you find crucial building science information on plans and help create an estimate for you. It’s completely accessible with chat and super simple, you just message it through WhatsApp. 

I’m bringing on beta users and it's still early so please DM if you're interested or see more here.

Hello!

Trying to buy a home and I saw there spray foam.

What are some questions to ask the builder, hvac, and inspector to ensure that it is not off gassing and that the attic is well ventilated. What are some measures to put in the home to ensure we don’t breath the voc? Like air purifiers for each room? Please help and be kind as Im trying to do my best.

Pictures of the attic. Ugh i hope it’s not in the walls. What is the cost to rip this out?

Thinking of buying the place but this seems pretty shoddy. I’ve heard of off gassing and vapor barrier issues.

It’s a brick home on the exterior with block foundation.

Thanks for any pointers or opinions on what else to watch out for.

Thanks for info so far. back again and decided to replace my basement builder grade insulation (pictured). CZ6 southern Ontario.

The question: my stud wall is currently framed off the concrete foundation wall. The gap between the stud wall and concrete is 1”+ in places, and some places as low as 3/4”. Framing is finished, and I stick framed, so it will be hard to move without tearing it all down and starting over. There is sill gasket under the bottom plate fyi. All the spray foam contractors are saying it is fine because they want the job, but the info online just says “1-1/2” is best, but nothing definitive.

Will I be ok with 2 or 3” of CCSF, even though in some places it will only be 3/4” spray foam in behind against the rear of the 2x4 studs and 2-3” spray foam inside the stud bays? Another way to put it - Should 3/4” ccsf + 2x4, combined with 2-3” of ccsf in stud bays provide a Vapor barrier in CZ6?

If not - will a suitable alternative be: 3” of spray foam in rim joists + air gap and r14 rock wool in stud bays and a smart vapour barrier on stud face? This won’t meet r20 code but my feeling is it will be ok for moisture. My basement is not very cold and spray foaming the rim joist will go a long way. Option 1 is spray foam the whole wall but I don’t want to waste the money if I will not get a complete air/vapor/moisture/thermal barrier, and the wall still sweats or some other unintended result.

Thanks kindly for info

I am NOT a builder but I am building my own homeobvois answer it to simply case in wood but you dont know what you dont knowknowhutimeanVern? input/ideas please. .

Is this specific to concrete slab applications? Or old conceptual thinking? Or do they mean it takes a long time for the other surfaces in the room to warm up?

Because we have a wood framed floor with warmboard and slate tile on top and we went from 64F to 76F floor temp in 1.8 hrs during the cold snap yesterday.

What I didn’t track is how long it took the floor to cool down when I turned it off. I don’t have long term data trending set up yet, unfortunately.

Hi r/buildingscience ,

I've been working on this AI tool with a consulting firm to speed up on site condition assessments, investigations and any sort of report writing. Think of it as a co-pilot that can assess a space for building envelope deficiencies, help write the report and help you if you miss anything.

There's a video on our website here that shows how the AI can tag and describe photos so you don't need to waste time sifting through hundreds of photos.

Hoping to improve this further so if you'd like to try it out or give me feedback, let me know!

There are still a lot of people recommending spray foam on here, and it’s not becoming a better idea. Read these reasons if you disagree. Discuss.

Have had terrible air quality months after spray foaming a remodeled house (done by a reputable company). Have an ERV and tried months of venting with open windows and fans. No change in air quality. Finally got results back on air quality. Out tons of money with no real solution besides complete tear out and new roof. Great for thermal results, terrible for health.

Aerogel is being hyped like the best of all? But when I got some silicon aerogel powders in some solvent, it doesn't look like they can do any jobs that traditional insulations can do? It also looks very powdery and fragile. Could anyone expert in this explain it to me please?

Our house was pretty old and this was the first time we encounter a water leak in our room. Anyone know who should we call to helped us solve this problem?

Your help are greatly appreciated! Thank you!

Air conditioners must exhaust 'waste heat' which is blown out the condenser. And I'm just wondering: How much air is lost?

When our home's central A/C is running, I get blasted by a strong gust exiting the condenser unit outside. Wouldn't all/most of that air need to be replaced in order to avoid contributing to negative air pressure in the home? 🤔

We have several clinical signs of negative pressure when our central A/C is running: Strong draft coming from inside the walls, doors resist closing, poor IAQ, etc. (I also ordered a manometer so I can get exact measurements and am awaiting its arrival.)

I assumed the negative pressure was due to duct supply leak(s) since they're housed outside the building envelope and most energy auditors report an average of 10%-30% duct leakage in systems they audit. So, we stopped using the central HVAC and hooked up 5 individual, standalone A/C units. We also covered up all the central return/supply registers in the home.

Believe it or not, things actually got worse. It appears we have more negative pressure, not less. So, now I'm wondering if it's even possible to achieve a net zero pressure value in a home while the A/C is running. Even if we have mini-splits installed, the fundamental way A/Cs function will always mean some air loss. I guess the only permament solve would be to install one or more fresh air intake(s) that pull in enough air to compensate and just take the hit on utilities?

P.S. We also have 4 ductless, wall-mounted ERVs installed in the home which (are supposed to) operate at a slight positive pressure. But I don't think it's anywhere near enough to compensate for the lost air because we still have clinical signs of poor IAQ even with them running. We also have 6 IQAir purifiers running at 170cfm 24/7. It helps, but again, it doesn't seem to be enough to keep up with whatever gets brought in by the negative air pressure.

Thoughts? 🧐

tl;dr My house (Climate Zone 5, bordering on 6, in Michigan) is gutted down to the studs (long story). I have a golden opportunity to insulate it well during reconstruction, especially since it needs a new roof and siding. I need help figuring out what to do when it comes to insulating the vaulted ceiling, and I cannot risk using spray foam for health reasons.

My values:

• Energy efficiency and moisture control. I am willing to spend more to get an improved building envelope. Ideally it will pay for itself with lower heating and cooling bills eventually, but maybe it wont.

• Comfort. I expect it to be challenging to cool the loft area in the summer. I'm going to install two ceiling fans up there, but I think insulation is my first line of defense.

After reading up on https://www.continuousinsulation.org/ and elsewhere, I feel pretty good about my plan for an exterior wall assembly: R-13 Kraft-faced batts in the 2x4 stud wall cavities, and two inches of polyiso continuous on the exterior (also about R-13). If that doesn't sound good to you, please tell me why.

I just don't know what makes sense for the attic / roof. On one hand, maybe the traditional vented soffit / ridge vent / baffles / blown-in method would work just fine. The problem that I'm anticipating there is that the edge where the vaulted ceiling meets the vertical wall is close to the roof line, so would putting baffles there take care of ventilation needs? On the other hand, even if that traditional vented setup didn't have a moisture problem, I wonder how challenging it would be to cool the loft area in the summer given that it would be surrounded by unconditioned space. So is the move to turn the attic into a conditioned space by adding ~4 inches of polyiso (R-26 there would be 40% of an R-26 continuous + R-38 batt assembly) on the roof and closing up all the vents? Another complication is that the house has a large attached garage that is currently "separated" by some plastic sheeting in the attic that flaps in the breeze. The garage extends to the right in the 3D render (I didn't have time to model the garage too, but I can if that would be helpful).

I've been able to find local structural engineers, exterior contractors, and insulation contractors, but nobody that specializes in building envelope design. Would a building envelope consultant need to make a site visit, or could they get a design together remotely?

I appreciate why people get PhD's in this stuff and I'm realizing that a house is a complicated organism. Thanks in advance for your input

It was a beautiful day for a roof inspection in Oregon. These were what we found on a relatively new roof...

Can someone tell me what countries in the world sells and uses SHS tube posts say 75,89,100,125,150,200mm square in domestic construction ? I realise USA calls them HSS Tube and does them in imperial. 21/2" ,3" ,4" ,5" ,6" ,8" with varying wall thicknesses. In Australia we use them for balcony/verandah posts and supporting floor bearers on a sloping site.

Australia and others ?

Hi everyone,

Long story short, i didnt like to be a homeowner since house seemed to be a fragile investment with lots or possible problems (wood frame rot, termites, leaky roof, drywall cracks because the amount of snow we are getting on the roof....)

What i am looking for is plan for simpler building, costing a bit more if needed, with efficiency in mind. Steel framing, AAC, metal roof, you get the pictures.

Is there any company specializing into those buildings?

Thanks.

Curious how folks here think about knowledge-sharing. I’m on the infrastructure advisory side and I keep seeing the same pattern: excellent building science input on things like thermal bridging, condensation risk, or air barrier sequencing gets handled well within the envelope team, but rarely surfaces in a way that’s visible to other professionals.

You might be sharing lessons internally, in company libraries, project records or specialist forums, but architects, GCs, and trades working on similar challenges might never see them. Not because the insights aren't valuable, just because there's no shared venue where these things cross lines.

I’ve been thinking a lot about this and ended up building a space called AEC Stack where technical insight can be posted outside those silos. If you've solved tricky performance issues before, what would make you actually take the time to share that publicly?

If you've ever thought “we fixed this exact thing last year, but no one outside our team will know,” you're probably the kind of person I’d love to hear from. I'll be in the comments.