condensation

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hi ppl, just finishing off some work on a new build kitchen extension. See pictures.

The issue is im getting moisture building up below the lintels. Through the day/ night it builds up into water droplets, when i wipe off they come back. Its only happening close to the door/ window side of the lintel i.e with 2 inchs of them along the whole lintel.They are installed at a slight angle but im sure there is no cavity tray. There is also no weep holes and soffit vents installed at the moment. (ignore the foil tape was just a test, it still happened.)

Please how do i fix this

Thankyou
 
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If this is traditional cavity wall it looks like you have set the window far too forward within the reveal, the window should sit back from the outer face by about 75mm. Where you have fitted it you will be getting a cold bridge occurring and thus condensation. How have you closed the cavity at the cill/jambs?

https://environment7.uwe.ac.uk/resources/constructionsample/Conweb/walls/catnew1.jpg

https://environment7.uwe.ac.uk/resources/constructionsample/Conweb/walls/catnew2.jpg


Is the lintel insulated?
 
hi, its cavity wall with 100mm insulation with brick and thermalite blocks.

at the bottom there is a cavity closer - 100mm celotex with dpc crossing the two leafs. at the sides i have used http://www.wickes.co.uk/invt/153229 with some expanding foam to stick the edges down. At the jambs the cavity closer dpc over laps onto the sides a little.

Thanks for the pictures, The lintel is insulated with polystyrene, although the small area above it to the flat roof of 8 - 10 inches i dont think is insulated
 
Its hard to say exactly from photo's but I would say that the rear face of the window is near enough in line with the rear face of the outer skin? Even with an insulated lintel a cold bridge is going to occur and the result is as you have found. Better to find it now than after the reveal is plastered though.

So you have improvised cavity closers, at the cill we is a dpm between your Celotex and the outer skin as Celotex is not designed to be used against an outer skin as it will absorb moisture. Have you done the same at the jambs?
 
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yeah the glass is about in line with the rear face of the outer skin. Thats the next job plaster, but not now.. argh

I made the closer yeah after reading the reviews on screwfix. I didnt use any dpm to line the wall where its in contact. I see thats a problem. I've had a look and i cant even feel its there, think its dropped down on one side atleast. I will start again with something like this


Is the membrane i used on the sides ok ? or should i replace it. On the jambs - you mean the cavity on the sides of the door ? its just that black insulated membrane in the pic from top to bottom.
 
Ideally you should install a proper cavity closer on the jambs (the sides) too, given the cost of a cavity closer it really is a false economy not to, any issues with damp in the future will be a royal pain in the backside and expensive to sort out.
 
thanks freddy i'll rip off the black dpc for some proper closers. This wont help much with the lintel will it ? how about insulating it from underneath as theres enough clearance on the frame. I could even take the soffits off and put some insulation on top if there is not much. At the moment the room is quite cool at 15- 16 degrees (london) drops to 10 - 11 at night. Rest of the house is 23 degrees.
 
Well setting the frame back will help no end, also in theory your trickle vent will allow that moist air to escape rather than condensing on the frame.
 

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