Is it normal with some leakage into roof/sheathing when underlayment has been laid
This screams CONSTRUCTION FRAUD in my world.C Charlie01 said:
1. A roof underlay should be completely waterproof. (Otherwise, there's no point in having it at all.)
2. That they see no risk of mold if you insulate and seal a wet roof with leaking underlay felt speaks for itself loudly. CONSTRUCTION FRAUD. 100% guaranteed mold and likely even rot. Exactly the same principle as single-stage sealed facades.
3. Furthermore, they shoot themselves in the foot by first claiming that the water is due to condensation, only to then claim that any cracks won't matter since outer felt is going on. Either the water is due to condensation, or it's because of a non-watertight roof underlay.
The builders obviously know this is unacceptable but clearly lack both professional pride and integrity.
A small correction to an otherwise sensible postOldboy said:
The above is not correct regarding surface roofing felt. Of course, you can lay base roofing felt that is watertight in the same tough conditions as you use surface roofing felt, but it costs much more than it benefits in most cases (it basically requires welded base roofing felt), but it is still advantageous to use some type of base roofing felt even though it doesn't become 100% watertight.
Of course, it should not leak during construction, but this is usually solved more reasonably with tarpaulins or simply by installing the surface roofing felt immediately after.
It should be noted that it's not always easy to board a roof and make it waterproof, with weather and wind against you, and if it's cold, the adhesive edge doesn't work very well...Dr Benz said:
Some leakage should be expected during the construction process, but these leaks should be fixed as soon as they are discovered...
There are no companies that build 💯% waterproof roofs with the underlayment/membrane, success is possible if the weather is favorable and no nails are misaligned, etc.
The important thing is to seal as soon as leaks are detected and to let the roof sheathing dry naturally...
Some examples straight off the top of my head, besides the fact that it obviously increases safety during construction.
1. It provides a better surface for installing the top felt than just on the roof decking, which is actually allowed.
2. Fire protection since top felt is often welded with a propane torch. (Varies in importance depending on the construction)
3. Even though it is not 100% waterproof, it significantly increases safety compared to no underlay as small leaks (which are still the most common) probably won't penetrate and, at best, you can detect them and repair the top felt before causing damage.
Gas torch may not be used if non-fire-protected material lies underneath.. on rough timber, it is the underlay felt that serves as that...Rickard. said:
According to whom?Rejäl said:
I think it's a perfectly reasonable guideline to follow, but as far as I know, it's not a written rule that must be followed, but I might be wrong.
Heta arbeten might be good to look at…
I have looked at hot work on a few occasions and they don't go into detail on how to lay a roof but only set requirements for the propane burner.....Rejäl said:
But you must never have an open flame against combustible material, no craftsman is allowed to do this..
There is no law prohibiting you as a private person from doing it, but I believe that all insurance companies will deny you compensation for it, it is quite stupid to set fire to raw boards...
I'm including a chat inquiry to BMI Sweden about it..
https://experthjalp.bmisverige.se/org/bmisverige/d/papp-direkt-pa-raspont/
According to hot works, you should never use an open flame for waterproofing welding.....Rejäl said:
A propane torch with an enclosed flame is still a propane torch.
You can do as you like, but I've never heard or seen it being done, and all roofing companies require underlay paper...
If you want to do something at home, go ahead, but it's not something professionals do...
Ok then you should be knowledgeable..
However, there are membranes you weld together that might work, but I've never heard of them being used on houses since they require welding, which the carpenter doesn’t have the knowledge or tools to handle..
I have control...
It is entirely reasonable for the companies to demand it.
I am now leaving this discussion.
It is entirely reasonable for the companies to demand it.
I am now leaving this discussion.
The roof has three layers to keep moisture away.
1. The outer layer, which can be tiles, metal sheets, or whatever roofing material you have
2. The underlay
3. If the underlay starts to leak, the wooden board should swell and seal
Normally, 3 should never be necessary; whatever 1 does not manage to handle should be managed by 2. I would prefer the wooden board never gets wet or comes into contact with moisture at all. As someone wrote, a tarpaulin over the wooden board if you haven't managed to lay the underlay yet. Once it's on, you can calmly wait (I believe it's usually 6 months according to the underlay manufacturer) before applying layer 1.
1. The outer layer, which can be tiles, metal sheets, or whatever roofing material you have
2. The underlay
3. If the underlay starts to leak, the wooden board should swell and seal
Normally, 3 should never be necessary; whatever 1 does not manage to handle should be managed by 2. I would prefer the wooden board never gets wet or comes into contact with moisture at all. As someone wrote, a tarpaulin over the wooden board if you haven't managed to lay the underlay yet. Once it's on, you can calmly wait (I believe it's usually 6 months according to the underlay manufacturer) before applying layer 1.