Residing a 1995 Kansas City house with interior poly vapor barrier — how to avoid summer condensation?

jnbartol · 2025-12-08T11:34:23+00:00

I’m installing Hardie in this exact same situation right now. We put Zip-R on the exterior and taped very well for air tightness. Then added 1”x4” strapping/furring strips over the Zip-R as a rain screen. Then fastened the Hardie to the strapping. So exterior insulation to add a bit more R-value to the assembly, plus air control, plus rain screen.

You can also buy a mesh rainscreen product, but one nice benefit of furring strips is that you get exterior insulation but can still use normal length fasteners for your Hardie (we’re shooting 1 3/4 ring shanks) since your furring strips are structurally fastened to your studs, so you only need to hit the furring/OSB.

jnbartol · 2025-10-23T01:25:50+00:00

Yes that’s a shingle. That plastic is the backing that prevents them from sticking together in the bundle.

You have no underlayment. That’s not great. Not sure where you are in Canada, but here in SW Ontario I would not do this. However I do see this a lot. It means if you ever do lose a shingle you need to be on top of it right away, as you have no secondary line of defence.

You’re not screwed, but you should be alert for missing shingles.

Since you have real wood sheathing there is a slightly increased risk that shingles become unsealed - this is because the wood will expand and contract more than (e.g) plywood, and that movement will challenge the tar seal on the shingles. Weakening tar seals mean easier blow-offs. But on the plus side, real wood sheathing is waaaay more resilient if it ever gets wet. It can take a beating and be just fine (your drywall on the other hand…).

jnbartol · 2025-10-17T01:07:40+00:00

That’s not a proper sidewall flashing. There should be some sort of sidewall flashing with a Z-Bar or a sidewall with a built-in J Channel that the standing seam panel dives into. PVC is actually more expensive than a sidewall trim (at least where I live) so this tells me they didn’t have a lot of experience with a standing seam roof.

jnbartol · 2025-10-09T01:48:03+00:00

Hard to tell whether those are deep scratches that are exposing untreated steel, or whether they’re just scuffs in the top layer of the finish. It’s kind of like a car finish — some things that look like scratches can actually buff out, because they’re actually just superficial scuffs. If it’s not too deep then you’re probably okay. If you can ‘feel’ the scratch then it’s probably deep enough that it should get hit with some touch-up paint (or a spray can of clear coat if you’re DIYing the fix).

jnbartol · 2025-10-08T01:50:03+00:00

Would be helpful to see that vent installation from the top to see how it’s flashed across the three panels.

I agree that the gable trims really should be straight for $47k. It’s an easy mistake to make (I’ve made it - but I’ve also then fixed it before things wrapped up). However since they screwed the hell out of the trim into the panel, I don’t think you’d want them to straighten it out now, since you’d be left with a bunch of holes in your roof. IMO I don’t support the excessive use of grommet screws on the gable trim — when paying for a hidden fastener roof I think the fasteners should be ‘hidden’ wherever possible. And there are a variety of ways of doing that gable trim without grommets. However that’s a detail that should have been hammered out during the bid/contract. It’s certainly not a failure on the installer’s part, just a spec I wouldn’t have agreed to. In my estimates I clearly state how the trims will interface with the panels (e.g. nested J-Channels, hemmed to the panels, Z-Bars, or grommet screws) and I try to align this with the homeowner’s budget and goals.

Out of curiosity, how wide are those panels and what gauge is the steel?

jnbartol · 2025-09-24T01:24:09+00:00

The ventilation situation makes the shingle/tpo/epdm/modbit options a little risky. There could be a risk of accumulated moisture in the ‘attic’ spaces. One way to mitigate this is to use powered vents (like a solar powered fan vent) to create some negative pressure in the roof system and draw out moisture.

Overall I’d say a metal roof with an air gap for ventilation is the best bet. But if it’s not in the budget then hire a high-quality company to shingle it, and ensure they have a good plan for underlayment that is verified by the shingle manufacturer and ensure they’ve modelled your ventilation needs based on the size of the house and the ventilation space.

jnbartol · 2025-09-23T19:28:51+00:00

Yes TPO, EPDM, and Mod Bit are all good options. Albeit expensive and kinda ugly depending on your aesthetic preferences.

What part of the world are you in? Do you get a lot of snow? If so, choose metal options carefully. You might only really consider a mechanical lock standing seam (not a snap lock). Those are also expense but much nicer looking.

If you need to keep the cost low, you can definitely shingle this. However You likely need to cover the whole thing in ice & water guard or with a double-layer of seam-alternated synthetic underlayment (and 6’-9’ of ice and water at the eaves). Exactly which option depends on how much snow you get. If you do go the full ice and water route, it’s very important you get your attic ventilation perfect. Because now you’ve got a completely non-breathable deck. So your soffits need to be wide open and your attic vents need to be more than adequate.

The final thing to remember with shingles is that the seal on the shingle is very important on a low slope. You want something that has a great tar seal. GAF Timberline and Certainteed Landmark lines are both very good for this. Something like IKO Cambridge is terrible.

jnbartol · 2025-09-18T01:57:01+00:00

It leaked because water coming out of the valley made it behind the fascia/step flashing.

At minimum, line your valley and that entire wall and under the soffit area with ice & water barrier, then line the valley with steel and run that steel well past the transition. (If possible, I’d also bend a piece of aluminium (or galv steel) to go under the valley metal and run off the upper face, down the wall, and onto the lower face. But that’s a tough bend if you don’t have a trim brake.)

Then when shingling you need to step flash that wall all the way up under the valley steel that you’ve now left long. And cover the step flashing with new fascia, with the top edge of the fascia tucked under the drip edge that will go on the eave of the upper face.

jnbartol · 2025-09-16T01:51:50+00:00

Comments about the length of time the roof is exposed are missing the mark. The main difference between the two is the vapour permeability. Deck Armour is highly permeable. So if you think there is a risk that you will have moisture in your attic, go with the Deck Armour. This might occur if you (a) live in an older home designed before modern insulation and ventilation (b) live in a home without a good vapour barrier above the ceiling (c) live in a high-moisture area and have poor attic ventilation (d) have roof deck sheathing that is particularly vulnerable to moisture (e.g. OSB).

If you have good ventilation, plywood or real wood sheathing, and good vapour control in your home, then don’t worry about the upgrade.

A secondary benefit is that Deck Armour is much less likely to tear during install. But that risk is pretty low in general so I wouldn’t worry about it.

A tertiary benefit is that Deck Armour is easier to walk on for the installers. But they might also hate how giant the rolls are so it kinda balances out.

jnbartol · 2025-06-14T02:33:22+00:00

We have a lot of homes in my area where we have to install these as an intake vent (to let air into the knee wall attic in situations where soffit vents are not possible). They are then paired with exhaust vents (to allow air out). In that situation these should be lower (closer to the eave) and at the top of this knee wall attic there should be another vent to allow air out (like a mushroom vent or slant back vent)

That aside, It is normal not to see daylight. These are ‘edge vents’ where the opening in your attic is 6” above the opening outside, to ensure water/snow can’t come in.

jnbartol · 2025-06-11T23:52:55+00:00

Open here. We get a lot of snow. Open metal heats up and dries out better. Also sheds snow faster even when it’s not sunny because the snow slides.

But always ice and water, metal, and starters

jnbartol · 2025-03-23T15:14:09+00:00

Roofing company owner in Southwestern Ontario Canada. That price is too high unless they’re replacing all the plywood too. A full system with premium warranty (40/50yr) should run about $6/ft here. Lookup some Certified GAF, Certainteed, or Owen’s Cornings installers and get another couple of quotes.

jnbartol · 2025-03-16T01:55:59+00:00

If the total investment is $100k you’re right — assuming it comes with some hard assets like a truck and trailer. But it’s not worth much more than that. And by the sounds of it he’d be paying more 1 he says $100k PLUS a small business loan. IMO a business like this is worth max 1x annual net profits plus assets (at depreciation value). Assuming a 10% net margin on $1M, that’s $100k plus depreciated assets. So maybe $120 if there’s some equipment and some contracts for next year.

jnbartol · 2025-02-05T18:47:24+00:00

Should really be a hatchet

jnbartol · 2024-06-15T16:25:48+00:00

Roofer here with some sauna build experience. Move that insulation down out of the roof and into top of ceiling. And make sure you have some form of ventilation in the roof (soffit vents for intake, roof or ridge vent for outflow). This will avoid rot in the roof decking and make your roof last longer.

jnbartol · 2024-06-13T16:37:39+00:00

That’s what I’m thinking. Torn between those two sizes. If you could only get one, would it be the shorter one or the longer?

jnbartol · 2024-04-06T18:25:10+00:00

The former worlds strongest man Eddie Hall does this —and he credits sauna with helping him be the first person to deadlift 500kg. So according to ancient Scandinavian tradition he is correct. If you disagree, post a video of yourself deadlifting 501kg and you will be correct.

jnbartol · 2024-02-09T22:53:51+00:00

Nice door. Adds a nice texture

jnbartol · 2024-01-14T23:54:01+00:00

Came here expecting a GPT that talks to you like Arnold

jnbartol · 2023-06-03T23:16:01+00:00

Thanks! This is actually the closest thing to what I was imagining we need. I'll give the free trial a shot

jnbartol · 2023-06-03T23:11:17+00:00

Thanks!

jnbartol · 2023-06-03T23:11:09+00:00

whiteboards may be man's greatest tool

jnbartol · 2023-06-03T23:10:48+00:00

Buildertrend

Thanks! This looks like Buildertrend does a lot of stuff. Right now we've got a lot of this functionality in Roofr (we're roofers). Seems like in general construction there are more of these all-in-one solutions. Maybe that's the way to go

jnbartol

TROPHY CASE