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information regarding rockwool


Mike_scotland

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Hello Group,

im sitting here wondering if im stupid or my builder is so hopefully someone can help and educate.

my wife was at our build today and the builder has his guys applying the 150mm rockwool on the walls downstairs - but we have no roof or windows in yet? is this not silly?  the problem is its wool then vc foil so if he puts all this on the we wont see if the wool is wet....

there is sarking and roofshield(green stuff) but literally no slates yet??

he was trying this a month ago to put in the wool but we agreed it wasnt pratical due to the fact there is no roof on... but now he is doing it anyway so im left wondering if it is fine why did he stop it a month ago and if it isnt ok why is he doing it now?

thanks!

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Just now, Russell griffiths said:

If the roof shield is on it should be dry inside, is it not. 

not 100% as the upstairs was wet at the weekend, although it was a bad storm. im really not wanting to take the chance, but i just wondered what others opinions were

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42 minutes ago, Russell griffiths said:

If the roof shield is on it should be dry inside, is it not. 

are you thinking its ok with the rockwool application? without the roof on, im just looking for peoples input really.

its just we brought the potential of water ingress to the builders attention and he said that "were right we wont do it" suddenly now its in hahaa so whats changed

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Just now, PeterW said:

Why not sheet the windows ..?? Heavy poly and a staple gun and make some frames from battens ..? Get some dry working space plus allow trades to continue ..??

 

in all honesty they are meant to have heavy duty poly on the windows keep[s blowing off everytime we are up.

also my biggest concern is the rockwool getting wet? the roof isnt on and the weathershield is weatherproof not water proof. and i have seen it with my own eyes it is pissing in at times.

at the end of the day im looking for fellow builders/ trademens opinions etc.

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3 minutes ago, Mr Punter said:

You don't want Rockwool getting soaking wet and then sealing the wet in.  For the windows I have used the clear heavy duty reinforced tarp wrapped around battens.

exactly the roof isnt on, we agreed a month ago to wait until slated. and hes went on his own back and done it

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I’ve been in many many timber frames houses with no windows and the roof just tiled and felted and not seen any moisture internally other than some minor localised damp at openings in walls. So I am confused. The underlay should not be leaking if complete (just waiting cladding). Very strange. It is pretty common in a busy housing development to see fitting insulation and even plasterboard prior to slating roof.

Edited by Gordo
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18 minutes ago, Gordo said:

I’ve been in many many timber frames houses with no windows and the roof just tiled and felted and not seen any moisture internally other than some minor localised damp at openings in walls. So I am confused. The underlay should not be leaking if complete (just waiting cladding). Very strange. It is pretty common in a busy housing development to see fitting insulation and even plasterboard prior to slating roof.


the roof isnt tiled or slated though thats my point?

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6 minutes ago, Mike_scotland said:


the roof isnt tiled or slated though thats my point?

Sorry that was a typo. I meant battened not tiled. If it has battens and underlay on it should not be leaking significantly.

Edited by Gordo
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5 minutes ago, Gordo said:

Sorry that was a typo. I meant battened not tiled. If it has battens and underlay on it should not be leaking significantly.

no it isnt leaking alot just is leaking... and i know it is a building site, but my problem is if it gets wet the insulation and its all sealed up how are we meant to see this? we cant x ray the whole house.

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9 minutes ago, Gordo said:

Sorry that was a typo. I meant battened not tiled. If it has battens and underlay on it should not be leaking significantly.

i appreciate the input though mate, im just looking for peoples opinions.

i would reluctantly accept the wool being in with no roof if we could see any damage/damp/wet but i dont think we will they have it all foiled in.

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19 minutes ago, Gone West said:

I wouldn't fit insulation unless the building was weathertight.

Definitely. But what I was getting at is the underlay shouldn’t be leaking, just before slating. That would concern me unless a spot repair was needed.

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the Roofshield should not, in my opinion, be leaking! in our place when the Roofshield went on the only rain that got in was through the open windows. I've now sheeted some of them with plastic sheeting, albeit rather thin plastic sheeting which I'm thinking of replacing with thicker stuff! in those rooms I've started putting the mineral wool between the studs as it's dry in there now even with just the Roofshield on the roof.

 

I'd be asking your building why the roof is leaking, even in small amounts, where the Roofshield is.

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You keep saying the roof is not on,  but as others have said, the roof shield should not leak. Definition of watertight is felt on. IMO. I had rockwall batts installed in the cavity throughout the build, rockwall installed in warm roof before felting. Slating weeks afterwards. Windows installed last. As an aside I was worried about damp in the cavity insulation due to fierce wet weather on our western wall (brick) when I core drilled fir the MVHR the outer 1” was soggy from water penetration through the brick but it did not wick inwards anymore. Since I coated that wall with waterproofer the insulation has dried out, I did not apply the waterproofer till after a good dry summer spell.

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12 minutes ago, joe90 said:

You keep saying the roof is not on,  but as others have said, the roof shield should not leak. Definition of watertight is felt on. IMO. I had rockwall batts installed in the cavity throughout the build, rockwall installed in warm roof before felting. Slating weeks afterwards. Windows installed last. As an aside I was worried about damp in the cavity insulation due to fierce wet weather on our western wall (brick) when I core drilled fir the MVHR the outer 1” was soggy from water penetration through the brick but it did not wick inwards anymore. Since I coated that wall with waterproofer the insulation has dried out, I did not apply the waterproofer till after a good dry summer spell.

why do i bother with 8k worth if slate then if i can just use roofshield? 

it shouldnt leak but thats my point, it is and there fitting insulation.

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8 minutes ago, Mike_scotland said:

why do i bother with 8k worth if slate then if i can just use roofshield? 

Because it’s backup in the long term and temporary in the short term.

9 minutes ago, Mike_scotland said:

it shouldnt leak but thats my point, it is

Then I would ask your builder why? And get him to rectify it.!

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2 hours ago, joe90 said:

Because it’s backup in the long term and temporary in the short term.

and Roofshield has UV protection for only a few months so need to slate it as soon as possible really

2 hours ago, joe90 said:

Then I would ask your builder why? And get him to rectify it.!

+1

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Exactly. Don’t treat the symptoms of your problem before you treat the cause. 
 

aa said above the underlay is not a cladding it is a backup to water ingress and to stop a storm ripping all your slates off, should just a few come off and allow wind penetrates. I think this is the reason Scotland favours timber sarking.

 

”roofshield” is a good product which doesn’t leak. It’s the way it’s fitted that needs looked at.
 

The damp insulation is undesirable but will eventually dry out, as the wall element should be breathable. But 20 years down the line, if the slates fail and allow some water to penetrate maybe intermittently, in a storm or gusty period, the underlay will not save you from water ingress to the fabric / interior. Then it will be a problem you wish you had sorted. Get it sorted now before allowing slating to commence

Edited by Gordo
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