# Water from behind Mastic



## Tripster (27 Feb 2021)

Hard to explain but had Mastic replaced around windows by site last summer (new build). Noticed today water dripping from behind and white residue on frame. Wondered where the water would be collecting and how it’s behind the render. Any ideas ?


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## Slick (27 Feb 2021)

Hard to tell by the pictures but are you sure it's not supposed to be like that?


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## Slick (27 Feb 2021)

If it is behind the render you would here it if you tapped it.


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## Tripster (27 Feb 2021)

Slick said:


> If it is behind the render you would here it if you tapped it.


If I push the mastic gently, more holes open and water poles out then stops.
Tapping the render does nothing


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## TissoT (27 Feb 2021)

The frame has weep holes in they should show on the out side of the frame or they are underneath

Water builds up inside the frame so they water needs to come out its normal.


View: https://www.youtube.com/watch?v=KZvPXNfafTM


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## Slick (27 Feb 2021)

Tripster said:


> If I push the mastic gently, more holes open and water poles out then stops.
> Tapping the render does nothing


If the render is solid then there is no water behind it.


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## Tripster (27 Feb 2021)

TissoT said:


> The frame has weep holes in they should show on the out side of the frame or they are underneath
> 
> Water builds up inside the frame so they water needs to come out its normal.
> 
> ...



Yep I see this on the rear door but the water is not in the frame it’s from holes in the mastic around edges and dripping out from top above window where it seals to render. Render is crumbly in places and when I pushed the mastic in one point it had a gap to render and water poured out. It’s the front room window and above the frame


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## Tripster (27 Feb 2021)

Slick said:


> If the render is solid then there is no water behind it.


Will go check all around above window. Thank you for the tip Hope it’s all solid


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## TissoT (27 Feb 2021)

Tripster said:


> Yep I see this on the rear door but the water is not in the frame it’s from holes in the mastic around edges and dripping out from top above window where it seals to render. Render is crumbly in places and when I pushed the mastic in one point it had a gap to render and water poured out. It’s the front room window and above the frame



I would need to see a picture of the above window.

Is there a sill (External) on the window above ?

The water could be collecting in the frame above a passing through.


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## Tripster (27 Feb 2021)

Slick said:


> If the render is solid then there is no water behind it.


Render solid, just mastic not sealed to render and holes all over. Water running from behind


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## Tripster (27 Feb 2021)

TissoT said:


> I would need to see a picture of the above window.
> 
> Is there a sill (External) on the window above ?
> 
> The water could be collecting in the frame above a passing through.


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## TissoT (27 Feb 2021)

Is there a window on the first floor above the down stairs window.


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## Tripster (27 Feb 2021)

TissoT said:


> Is there a window on the first floor above the down stairs window.


Yes, a bedroom window directly above like below


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## TissoT (27 Feb 2021)

I would be inclined to be looking at the window above the water is passing through from above.

The K rend rendering looks fresh so it not passing through there 

They look like a timber frame building.


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## Tripster (27 Feb 2021)

TissoT said:


> I would be inclined to be looking at the window above the water is passing through from above.
> 
> The K rend rendering looks fresh so it not passing through there
> 
> They look like a timber frame building.


Yes timber frame building. Will check upstairs window. Thank you for help, appreciated it


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## Bazzer (27 Feb 2021)

Are you sure there is no gap between the render and the frame? Years ago I had a similar problem with an upstairs window and capillary action through a tiny gap was the cause.


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## Tripster (27 Feb 2021)

Bazzer said:


> Are you sure there is no gap between the render and the frame? Years ago I had a similar problem with an upstairs window and capillary action through a tiny gap was the cause.


Found a gap and loose render on upstairs Window. Not sure if it’s the cause. Developer is a local builder and real A-hole. Controlling, arrogant & argumentative. A real joy to deal with


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## TissoT (27 Feb 2021)

Tripster said:


> Found a gap and loose render on upstairs Window. Not sure if it’s the cause. Developer is a local builder and real A-hole. Controlling, arrogant & argumentative. A real joy to deal with


You will have more than likely found the exit hole.

The house would probably hold a NHBC Certificate or equivalent I guess


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## Tripster (27 Feb 2021)

TissoT said:


> You will have more than likely found the exit hole.
> 
> The house would probably hold a NHBC Certificate or equivalent I guess


LABC but worthless. The builder is an arse of a man. LABC do nothing only play a go between. 
So you think the dripping is the exit hole and somewhere around upstairs window is where water is getting in ? Unless I can find it and prove it, they will no nothing


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## TissoT (27 Feb 2021)

Tripster said:


> LABC but worthless. The builder is an arse of a man. LABC do nothing only play a go between.
> So you think the dripping is the exit hole and somewhere around upstairs window is where water is getting in ? Unless I can find it and prove it, they will no nothing


I would say its coming from above yes. 

From what you have described Its the only only Place. It must be coming in at a alarming rate to show through the header above the ground floor window.


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## Tripster (27 Feb 2021)

TissoT said:


> I would say its coming from above yes.
> 
> From what you have described Its the only only Place. It must be coming in at a alarming rate to show through the header above the ground floor window.


That will help me sleep soundly tonight


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## Gunk (27 Feb 2021)

Tripster said:


> View attachment 576075
> View attachment 576077



That lintel looks as if it’s sagging


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## newts (27 Feb 2021)

There should be weep vents in front face of the render along the lintol at 450mm centres (when the underside of the lintel is rendered as in this case)? It may just expected moisture in the outer leaf of the wall requires a proper escape route i.e. weep vents.


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## Tripster (27 Feb 2021)

Gunk said:


> That lintel looks as if it’s sagging


Does it ? Had a few red wines so best check in the morning rather than now


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## the snail (28 Feb 2021)

Another possibility is that water is running down the face of the wall then back under the head of the opening - traditionally you would have a bellcast over the opening so that water would drip off rather than running back onto the window. Are you getting leaks on the inside of the window?


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## Tripster (28 Feb 2021)

the snail said:


> Another possibility is that water is running down the face of the wall then back under the head of the opening - traditionally you would have a bellcast over the opening so that water would drip off rather than running back onto the window. Are you getting leaks on the inside of the window?


No leaks on the inside. Been try here for a while so walls are dry, no water running down. Will have another good look today


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## TissoT (28 Feb 2021)

newts said:


> There should be weep vents in front face of the render along the lintol at 450mm centres (when the underside of the lintel is rendered as in this case)? It may just expected moisture in the outer leaf of the wall requires a proper escape route i.e. weep vents.


Its a timber framed structure weep holes are only used on masonry buildings


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## newts (28 Feb 2021)

TissoT said:


> Its a timber framed structure weep holes are only used on masonry buildings


On a rendered finish where the bottom face of the lintel is also rendered should there not be weep vents to prevent drips as the OP describes?


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## Tripster (11 Mar 2021)

So after the seriously heavy rain yesterday the water dripping has begun again, took 4 dry days to stop before, 
No obvious signs of a hole or water getting in from bedroom window above.
Contacted arse builder and he said first two year warranty ended that same day so go to LABC and don’t contact us from now on for anything
LABC are terribly slow to respond, take months to investigate a claim and £1000 excess on a claim so basically worthless. They also say that we are liable for any further damage if we fail to make good anything prior to outcome of the claim
Im thinking of having it investigated independently but don’t know if I need a builder or speak to the company that did the rendering with warranty. It’s not the rendering though I guess....
Any advice most welcome.


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## Gunk (11 Mar 2021)

I would speak to trading standards, if you can prove it was like that when you bought the house new, you could argue under the sale of goods act that it was not in “merchantable” condition when it was handed over.


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## Tripster (11 Mar 2021)

Gunk said:


> I would speak to trading standards, if you can prove it was like that when you bought the house new, you could argue under the sale of goods act that it was not in “merchantable” condition when it was handed over.


Afraid not, bought it new 2 years ago so the builders responsibility has ended and it’s LABC for next 8 years. They are to be fair unless. I thought the builder would just say I will take a look and see if anything obvious for you but it’s become apparent to the 60 home owners on the small development that he is a real peanut. Worried it’s doing some serious damage to the timber frame behind.


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## Mr Celine (11 Mar 2021)

What's the outer leaf actually made of? (blocks, bricks or something else) Are there any cavity vents?


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## Tripster (11 Mar 2021)

Brick with timber frame. It has a membrane which cannot be punctured from inside otherwise it effects integrity of the house.....so they say. 


Mr Celine said:


> What's the outer leaf actually made of? (blocks, bricks or something else) Are there any cavity vents?


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## Mr Celine (11 Mar 2021)

Tripster said:


> Brick with timber frame. It has a membrane which cannot be punctured from inside otherwise it effects integrity of the house.....so they say.









^^ A cavity vent. This is a 35 year old timber frame house (with 35 years worth of cobwebs on the outside) and is in Scotland where building regs have always been different and have changed over time. But newer houses up here have a lot more of these vents, usually above the lower cavity firestops and below the upper ones. (Note that the position of the vent in my photo suggests that there isn't a firestop at the top of the cavity. Cowboy builders are everywhere!) There is also a plastic membrane behind the plasterboard.


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## Tripster (11 Mar 2021)

Mr Celine said:


> View attachment 578095
> 
> 
> ^^ A cavity vent. This is a 35 year old timber frame house (with 35 years worth of cobwebs on the outside) and is in Scotland where building regs have always been different and have changed over time. But newer houses up here have a lot more of these vents, usually above the lower cavity firestops and below the upper ones. (Note that the position of the vent in my photo suggests that there isn't a firestop at the top of the cavity. Cowboy builders are everywhere!) There is also a plastic membrane behind the plasterboard.


Ah Im with you. Have vents all around bottom of house like old fashioned air bricks.
Nothing like that in your pic. House is almost all rendered


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## TissoT (11 Mar 2021)

Tripster said:


> So after the seriously heavy rain yesterday the water dripping has begun again, took 4 dry days to stop before,
> No obvious signs of a hole or water getting in from bedroom window above.
> Contacted arse builder and he said first two year warranty ended that same day so go to LABC and don’t contact us from now on for anything
> LABC are terribly slow to respond, take months to investigate a claim and £1000 excess on a claim so basically worthless. They also say that we are liable for any further damage if we fail to make good anything prior to outcome of the claim
> ...


I would call a building Surveyor and get a report it will be worth it in the long run.

I wonder if any of the neighbours have had a similar problem.


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## Tripster (11 Mar 2021)

TissoT said:


> I would call a building Surveyor and get a report it will be worth it in the long run.
> 
> I wonder if any of the neighbours have had a similar problem.


There is a residents facebook forum so I could ask wife to post a message and ask


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## TissoT (11 Mar 2021)

Tripster said:


> There is a residents facebook forum so I could ask wife to post a message and ask


Its a good place to start
I suspect some one may have had a similar problem.


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## newts (11 Mar 2021)

There should be weep vents to release the water in the cavity tray, as previously suggested.
https://keystonelintels.com/weep-vents-stop-ends/





https://www.nhbc.co.uk/binaries/con...ays-to-rendered-walls-revised-march-2017-.pdf
'Weepholes are required where render is returned back onto the window/door frame at the head of an opening'


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## Tripster (11 Mar 2021)

Nothing like that fitted. The lintel is completely rendered. For example in that picture where the weatherproofing membrane is thats where the water is running from, where the window is siliconed to the brick work/rendering


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## newts (11 Mar 2021)

Tripster said:


> Nothing like that fitted. The lintel is completely rendered. For example in that picture where the weatherproofing membrane is thats where the water is running from, where the window is siliconed to the brick work/rendering


They may be able to retrofit weep vents & it should cure the issue.
Both the builder & NHBC inspector have failed to follow NHBC guidance/good practise.
It's normal for some water to penetrate the outer masonary leaf, it should run down the inner face of brick/block & should drain away harmlessly. In this case it's tracking across between the render & underside of the steel lintel & out at the window face. If the sealant joint between window & render hadn't failed it could have tracked across the lintel over the window head & shown a damp patch internally.


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## TissoT (11 Mar 2021)

This will be the detail on the timber framed first floor

I have work on timber framed buildings on and off for over 30yrs

They vary slightly depending on specification from the manufacture.


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## newts (11 Mar 2021)

TissoT said:


> This will be the detail on the timber framed first floor
> 
> I have work on timber framed buildings on and off for over 30yrs
> 
> ...



The op's house has a brick/block outer skin, there will be a lintel & cavity tray?


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## TissoT (11 Mar 2021)

newts said:


> The op's house has a brick/block outer skin, there will be a lintel & cavity tray?


Op has confirmed its a timber framed building which I confirmed from the picture.

Ground floor outer skin is stone work and the first floor outer skin is Cement board with a K rend 

If weep vents where needed LABC would of specified them which is part of the 25yr certificate 

Op needs to contact LABC to try and solve the issue.


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## Tripster (11 Mar 2021)

TissoT said:


> Op has confirmed its a timber framed building which I confirmed from the picture.
> 
> Ground floor outer skin is stone work and the first floor outer skin is Cement board with a K rend
> 
> ...


Logged a case with them on 26th Feb but they haven’t even started to review it yet. The K rend extends down to ground floor window and under lintel


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## newts (11 Mar 2021)

TissoT said:


> Op has confirmed its a timber framed building which I confirmed from the picture.
> 
> Ground floor outer skin is stone work and the first floor outer skin is Cement board with a K rend
> 
> ...





Mr Celine said:


> What's the outer leaf actually made of? (blocks, bricks or something else) Are there any cavity vents?





Tripster said:


> Brick with timber frame. It has a membrane which cannot be punctured from inside otherwise it effects integrity of the house.....so they say.


It would appear from post above that it's brick outer leaf?


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## TissoT (11 Mar 2021)

Tripster said:


> Logged a case with them on 26th Feb but they haven’t even started to review it yet. The K rend extends down to ground floor window and under lintel


From a builders point of view I would wait for LABC to investigate the issue.

I have only had dealings with NHBC which I have found to good in the past.

I wish you luck and hope you get it resolved.


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## Tripster (11 Mar 2021)

Thank you @TissoT & appreciate your help and advice

Thank you


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