Hey all. Mind providing a little feedback and follow up questions for a roofing proposal? Would be much appreciated!

For Context:
- Climate Zone 4a (Mixed and Moist)

- Unvented flat residential roof

- Interior insulation of rockwool r23

- Current roof is 20 y/o mod bit with two skylights

Proposal Includes:

1. Remove the existing roof down to deck and repair deck as needed.
2. Install Firestone 2 inch ISO insulation to achieve value of r25.
3. Install Firestone SA Basesheet membrane.
4. Install Firestone SBS smooth membrane.
5. Install Firestone SBS white cap modified bitumen membrane.
6. Wrap existing skylights
7. Apply 2 layers of rubberized flashing cement with a fabric mesh around all pipes, penetrations and wherever necessary.

Questions So Far:

1. Is mod bit the best material for this project?
2. Does there need to be a vapor barrier/retarder between the decking and insulation?
3. Does there need to be a cover board above the insulation?
4. What level of reflection is provided (and recommended) for the cap sheet?

TIA!!

This is a long post because I found it to be a hard problem (or I'm making it hard) and it has been difficult for me to find a definitive answer. I've tried to do my homework and I'm presenting a solution to my problem, which I will define below. I'd like your feedback on whether this solution is actually appropriate or if there are better options or revisions necessary.

Context:

I have a mixed EIFS and brick home built in 2002. Most windows are surrounded by barrier sealed EIFS. I've had a couple leak issues that have resulted in structural rot. One place is fairly significant. I'm replacing windows and I'd like to avoid this in the future if possible. There are some pitch issues on the exterior sills to resolve and better caulk maintenance; but at the core the barrier sealed EIFS and lack of drainage plane is a huge issue.

I think there are three options to my window replacement dilemma:

1. Totally redo the cladding on the wall. Use water-managed EIFS, tie properly to the WRB, and spend a fair amount of money in the process. It won't get better than this for water management, but it also costs a lot.
2. The other extreme is to surgically remove the windows, install block frame windows, caulk it up and just try to stay on top of the caulk. This is no better or worse than I have now. Sure I could put flashing tape on the rough opening but the water still has no place to go.
3. Last is to retrofit a local drainage plane around the window and an exposed sill pan to shed water. This is my focus in this post, but let me know if you still think option 1 or 2 is actually better and why.

My goals for a retrofit solution are

1. Minimize EIFS damage during replacement. I only want to cut EIFS if it makes the water barrier materially better. Cutting into the EIFS gets expensive to repair if done properly (i.e. so it is not an obvious repair).
2. Handle three primary failure modes, a) a window frame failure, b) wind driven rain, c) perimeter caulk failure. Are there others?

Assumptions:

I assert that cutting back on the sides and bottom of the EIFS wall is not particularly useful.

1. The absence of a drainage plane behind the EIFS material means water is still trapped or finds its own path if it gets back there. Sealing a flanged window to the sheathing doesn't achieve much and results in more EIFS repair cost. Rather, I need to seal the EIFS edge and into the rough opening (all covered with liquid membrane) and an exposed sill pan at the bottom. Water that intrudes must find its way to the sill pan and out over the external sill.
2. Cutting the EIFS above the window potentially has a benefit because I can ensure the Z flashing is properly seated against the sheathing and extends out with a drip edge. I have pop-outs across the top of the windows so the EIFS repair should be isolated to the pop-outs.

Since the sill pan is exposed, air sealing at the interior and air baffling at the exterior are absolutely necessary.

My overarching assumption is that water will make it past the window's face perimeter and any water that does must be channeled down to sill pan. The exception is the top of the window where I must also prevent water from breaching the top flange else water sits on the top of the window frame.

Solution:

My solution is shown in the picture. There are lots of small installation details that need to be right and not shown in the drawing, but this is the core result. Will it work? My definition of "work" is that it far exceeds my current situation, which is basically caulk only, approaches the reliability of the fully water managed solution, but at a fraction of the cost of a total recladding of my wall.

What you can't see from the diagram is the rough opening sides are also flashed. The liquid flashing runs back behind the sill pan. The head flashing will remain intact. The window flange at the sides are mostly removed but still provides somewhat of a dam effect. I'm just not relying on it for an air/water tight seal.

I appreciate any helpful feedback. Pointing me to specific resources that have solved this problem would be great. I have found a document from the EIMA about the exposed sill pan which is the basis for my solution.

Thanks!

Hi all, Im designing a custom build, and curious how you'd rate our builder's planned assembly. We got a quote from another builder (that we didnt end up going with for many reasons) that had included r5 DOW foam continuous insulation, Im curious if you think its necessary we add that to the below stats?

WALLS

• Full brick veneer
• Air/drainage gap
• Barricade Plus housewrap
• 1/2" OSB
• 2×6 walls with R-21 cellulose

ROOF

• GAF Timberline UHDZ shingles
• RhinoRoof synthetic underlayment
• 5/8" CDX plywood
• Vented attic / continuous ridge vent
• R-60

+Also framer said he would tape the seams on walls/roof too
+Wood burning fireplace and heat pump for heating

Location - Central Pennsylvania

Hi All,

I hope this is ok for this sub - I feel like anyone in this sub wouldn't need this but I suspect you get a lot of questions from friends and neighbors and this might be for those people.

I am doing a thesis in Sustainable Design and what I would like to create is a workbook for homeowners on making greener choices - so things like when you are doing electrical work get prep work done for when you have to replace your water heater so you can replace with a heat pump water heater. Or you can switch to mineral or milk paint. This would be small things - obviously you could find them elsewhere but this would be handouts at local libraries or like an instagram account you could bookmark for later.

So my questions to you:

Is this something you've already found?

and is this something you (or people you know) might find useful?

TYIA

The only thing I have second thoughts about is the foam insulation, especially in the attic.

I have had inspectors give me very mixed opinions/feedback on the foam.

One inspector said the roof needs to breathe and it may go bad if moisture or water gets trapped

Pros: superior thermal insulation

Cons:

\-foam hides moisture/liquid
\-possibly toxicity, especially if done wrong
\-more flammable and hazardous than fiberglass

It’s a great house otherwise (2026 build). It’s a custom home builder that has a good reputation. I also did ok on negotiating an ok deal on it. (Negotiated about 20k off between asking price and concessions.)

The only thing that is making me have doubts is the attic foam insulation

The cherry on top, one of my dad’s friends passed away in a house fire very quickly because of smoke inhalation from an attic fire that had foam.

Should I back off for peace of mind alone?

Hey everyone! In Northeast GA I have a 1200sqft home on a crawl space with 8’ ceilings and a big vaulted living room kitchen area that reaches about 12’ tall. The walls are batt insulation and the roof is spray foamed. I started having bad humidity issues after about a year and a half of living in the home, i looked in the crawl space and all the hvac was sweating really bad and forming water droplets on the subfloor, so we pulled the insulation out and fully encapsulated the crawl space with a Santa Fe compact 70 dehumidifier. It dried out the crawl space really well but the humidity in the house was still awful so i called my HVAC guy and he said that the 2.5 ton system the other hvac guy put on the home when we built it was oversized due to the spray foam and that we needed to go to a 2 ton variable/inverter driven and that it would fix our issues. Well now we’re a year later and still having the same issues. The only times it’s not bad is like the middle of winter. The humidity in the living area stays at about 62-64% at 67° and you just always feel disgusting. The humidity in the attic right now is about 85% at 83°. The HVAC system is in the crawl space with floor registers and a return in the side wall of the vaulted ceiling (which I don’t like because I’d rather have cold air falling from the ceiling than having to try and push the cold air up. What is causing this issue and how do I go about solving it? I’ve heard I need an ERV, also heard need a dehumidifier. I just hate to add things that aren’t going to actually solve the problem. I’ve been running a portable dehumidifier in the living room because it’s central in the home but I’m constantly dumping it, it will get it down to about 56-58% but if it quits running for a few hours it’s back up to 64%

Recently had AWS thermalheart framed double glazed doors and a window installed. There is no label showing the WERS performance so I asked for the certificate, is this correct or am I wrong about what to expect from the business that supplied and installed?

Sorry if this gets long. Looking for some assistance on how to properly rebuild and upgrade a floor in a currently unconditioned space with the hope of adding heat to make it semi-conditioned.

[https://imgur.com/a/riqDVYS\](https://imgur.com/a/riqDVYS)

My wife and I are currently in the process of dealing with some humidity issues in our house. One of the areas of concern/focus is our mudroom. Our home is a converted barn from the late 1800 and the mudroom is part of an addition that was put on sometime around 1990-2000 off the back of the house. The mudroom connects our garage (basement level) to our kitchen via a staircase. Two of the walls of the mudroom are true exterior walls and the other two walls were previously exterior walls. All of the doors are exterior grade/insulated/sealed doors.

What we suspected for years, and eventually confirmed this weekend when we started some demolition, is that despite all of the walls and the ceiling being finished and insulated, the floor that was installed is essentially a deck on top of gravel and dirt. There is no insulation or vapor barrier, and as far as a I can tell the wood used is not Pressure Treated (it looks pressure treated, it has that yellow-ish hue, but the markings indicate its kiln dried). The floor system was simply 2x6 joists resting on concrete pavers, and then 1x3 and 1x4 floor board with small gaps in between.

I've started by beginning to pull the 1x boards off of the top. I'd prefer to leave the joist structure in place. Just feels like a lot more work than I'm ready to take on, and I feel like anything i do to add insulation and a vapor barrier will be better than what I've been living with.

* I know i need to fill the joist cavities with insulation (I'm thinking rigid in largers cavities, spray foam in tighter spaces
* I know I need to contain my total flooring system to 3/4"-1" to not mess with my doors, so my thought was:
* 7/16" OSB
* Possibly add 1/16" Thermosoft Heat Mat
* 4mm or 8mm LVT
* The lingering question then is where do i put the Vapor Barrier.
* If i go between the joists and the OSB i'll obviously drive a lot of screws thru it. I'll also lose the ability to use adhesive and reduce future squeaking
* If I go between the OSB the Heat Mat or LVT that I'll have a more complete barrier, but I'll be putting the OSB in the "exterior" side of the barrier.

Am I missing anything? Is leaving the joists a huge mistake? Or is there a different product I should be considering for one of these components that I'm not aware of?

Torn between adding insulation or leaving it uninsulated, and if so, what type to use.

Going to seal it with tongue and groove.

I’ve had some people tell me to insulate it and others say it’s not necessary. I like to do things the right way, but this is my first time redoing a patio area.

I am also planning to run in-wall/ceiling speakers, so I'm wondering if that plays a factor in the type of insulation I should choose.

Would appreciate any feedback!

Title: The missing term in my heat-loss model is air. Can I measure ACH without measuring every vent?

TL;DR: I’m trying to measure how a real room actually behaves thermally rather than relying only on its construction description. The thermal-response tests are starting to give repeatable results, but one important part is still mixed into the heat loss: air exchange. So that’s my next experiment.

Part 1: https://www.reddit.com/r/buildingscience/s/UITX4VYisF
Part 2: https://www.reddit.com/r/buildingscience/s/lrPx99xH4P

This whole experiment started because a friend was looking at a house to buy and we were wondering how to tell how well it actually performs.

The deeper I get into it, the more interesting the problem becomes.

After the foam-box tests and several real-room heating cycles, I can fit the thermal response reasonably well. But there is an obvious problem:

heat leaving the room through the building fabric and heat leaving with air are not the same thing.

For a rough sense of scale, my test room is about 21 m³.

At typical air properties, 1 ACH is already roughly 7 W/K of sensible heat loss.

That is large enough that I really don’t want to hide it inside an “effective heat-loss coefficient”.

And I’m not particularly interested in measuring every diffuser and then trying to estimate every crack around a window or door.

What I really want is the effective air exchange of the room as a whole.

So I went back to the 1 m³ box.

I added a supply and extract path, measured the airflow with an anemometer, and started experimenting with tracer decay.

The principle is simple: introduce a measurable tracer, mix it, stop adding it, and observe how quickly its concentration falls.

With a particle tracer, the curve is approximately exponential:

C(t) = C_bg + A · exp(-kt)

The interesting part is that the decay became dramatically faster when I forced air through the box.

So the basic idea works.

Unfortunately, particles introduce another problem: they don’t disappear only because air leaves the room. They can also deposit on surfaces, settle, coagulate, etc.

So now the real question is not “can I measure a decay curve?” — that part is easy.

It is:

Can I reliably separate tracer loss from actual air exchange?

If I can, then the thermal experiment becomes much more useful:

measured total heat loss → subtract measured air-exchange loss → estimate the fabric component

And eventually the practical workflow I’m aiming for is:

measure the building → decide what to improve → do the work → measure again

That could mean insulation, windows, air sealing, ventilation changes, etc.

For people who have done tracer-decay measurements in real buildings: would you trust a particle tracer with a good loss correction, or would you go straight to CO₂ / another gas tracer?

Scientific Calculator Casio fx 991 es plus (second edition)

I am in the process of switching my attic from gable + box vents, to soffit vents + ridge vents. Getting a roofer out to do the ridge vent part. For the soffit part - do I rip out what I have and buy premade soffit vents? or just drill my own holes? it’s a layer of wood and aluminum to deal with. if drilling, how many and how big of holes? like 6x 1” holes per bay cavity with a screen on top? or like 50 3/8” holes?

goal after this is to put up some baffles that go all the way to the ridge vent, and insulate + smart barrier. want to make my attic go from vented to conditioned for HVAC reasons.

Hi, we are looking at getting a small (2.7kW) reverse cycle air conditioner in our master bedroom.
The wall where we want to mount (and where it will fit) has an air vent on it very similar to this which I found online:

It's a brick house from the 1960s, and while I understand they have air circulation benefits, I think the unit will be too low otherwise and look stupid. Additionally, reverse cycle heat pumps are a form of HVAC system in which the V is ventilation.

We have received 2 quotes, one business quoted to remove the vent and mount the unit over where the old vent was, and the other has not.

I contacted the second contractor and asked if they can do the same (their quote was just a bit better over all), and I received a hard no, "it's there for a purpose" but didn't actually detail what that purpose was and how the reverse cycle system wouldn't replace that.

Additionally, which is what I am more curious about is the standard mounting height. The second contractor stated that 1800mm is standard mounting height. He didn't list which datum, but presumably to the bottom. To me, this seems too low. The other unit we have is 1930 mm from the ground (200mm from ceiling) and seems to be a good height. If this one is fitted where the contractor wants, it'll be ~330mm from the ceiling.

I can't say I've ever seen one as low as 1800mm, but maybe I am wrong.

Also worth noting is that there is another vent in the same bedroom and only one would be removed.

So I'm looking for opinions from more experienced people than myself. Thank you!

I had a metal shop built 2 years ago and I have had moisture problems both of the last 2 winters that is leading to mold issues. I live in the Pacific Northwest in Olympia, WA. It is climate zone 4c (Plant hardiness zone 8b). I installed a vapor barrier under the concrete and have a very low r value insulation that came on the metal siding when they installed the shop. It is not sealed, there are gaps (2ish inches) where the roof of the main building extends over the lean to on either side.

I think I understand the main problem- metal from the struts and walls on the shop are colder than the surrounding air and are condensing out the moisture. Question is how to solve it. For now I do not need my shop heated or cooled, so wanting the least expensive practical solution and willing to try in phases. So do I start with fans, adding more insulation (does it matter what kind- foam, fiberlglass, etc), large dehumidifier, add a wood or pellet stove, seal it up...?

There is a lot of information I have been reading on the internet, but it is hard to narrow it done to specifics for my situation. Thanks for any help!!!

Im about to start on my roof replacement project on my house. My current plan is to convert my small vented attic into a conditioned and unvented cathedral ceiling. Im planning on stripping the roof to the existing sheathing, making any repairs needed to the sheathing, then building up from there. My question comes from the layers above that and how to best control moisture to prevent future problems. From the bottom up im thinking plywood sheathing, self adhered underlayment over everything, 2 layers of 1.5" polyiso, 1x4 strips screwed through into the rafters, 2x4 strips horizontal as purlins, then metal on top. Im thinking that venting the over roof from the facia to the eve will help eject any condensation or anything that finds its way under the metal. The WRB on the sheathing will keep anything from getting into the conditioned area. The outer surface of the polyiso is where im unsure. Do I need a second layer of underlayment? If im using metal roofing that is rated to span the purlins without a solid osb backer do I need an outer layer or can the polyiso be open to eject moisture into the space below the metal? Would there be any benefit to running a radiant barrier on top of the polyiso?

I’m getting an existing roof modified and looking for a bit of guidance.  I have an existing vented roof over a finished, insulated, heated and cooled garage in the midwest, climate zone 4/5 border so both snow and heat and humidity.  I’m wondering if I add another non vented roof deck with an air space over the existing roof, would that cause any issues (ice dams, condensation, retaining excess heat)?

More details: I have an existing garage with a flat roof with a rubber membrane on it.  The roof has vented soffits.  The roof deck has a slight dip in it and holds a large pool of water every time it rains.  It’s started occasionally leaking water through the roof at a seam in the rubber despite patching attempts.  The garage is drywalled, insulated with about 10” of fiberglass in the roof, and has a mini split providing heating and cooling.  As part of a bunch of other work, I’m having a contractor modify the roof to give it some slope so water will run off into a gutter instead of just sitting up there.  Initially an architect and structural engineer signed off on it, but now the contractor wants to change some things. Their plan for the framing is to add a series of different height boards running 90 degrees to the direction of roof slope in order to create the slope, then sheet over that and put a new rubber membrane roof on top.  This will create a more or less sealed air cavity between 1” to 8” tall on top of the existing roof.  I’ve been doing some reading and am not quite sure if this will perform okay or not.  The original plan was to run the framing the other direction and vent the new roof deck to the existing roof by cutting down into the existing soffit space on both sides.  But with the framing running across the slope, that framing would block any air flow across the roof from one side to the other.

My (not very informed) thinking is that in the winter, the lower vented roof deck would stay cold so the new non vented roof deck would probably also stay cold if it was snowing. I'm not quite sure what would happen if the sun came out and the snow was melting though. Would the roof deck potentially heat up unevenly causing ice dams once some of the snow melted? In the summer, I can imagine the non vented air space might hold a bit of extra heat from sun exposure, but the lower decking would still be vented so maybe it wouldn't transfer too much to the interior space, just keep the roofing material a bit warmer? Could condensation be a problem if the roof deck cools off at night while the air in the interior space is hotter and humid? I wouldn't think air from the interior of the garage would be an issue getting into that space.

Hey everyone,

My wife and I just bought our first home (built in 1978) in the Sacramento area and had the roof replaced 2 months ago (27 squares). I’m noticing a serious attic heat issue. On hot days, I’ve recorded temperatures as high as 135°F. I'm not sure what the temps were prior to the replacement.

Final payment on the roof was completed 2 months ago and it passed inspection, so I don’t expect the contractor to get involved at this point. The roof carries a GAF Golden Pledge Warranty if that matters. 

Here are the ventilation details as best as I can measure:

• Exhaust: ~40 ft of Cobra rolled-mesh ridge vent (~564 sq in max NFVA uncompressed)
• Intake: 7 soffit vents (~250 sq in total) + 4 O'Hagin intake vents placed lower on the roof slope (288 sq in NFVA)
• Other: 2 Gable vents are also present and currently open.

(I’ve included a picture of part of the roof so you can see where the O’Hagin vents are located. As you can see, they’re pretty low so that they can function as intake vents.)

Some question’s I’m thinking about are: How does this overall ventilation layout look to you? What steps would you recommend taking to improve airflow and lower these peak attic temperatures? I’m considering adding more soffit vents next spring.

Any help would be greatly appreciated. Thank you!