porous chimney

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solway

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Hi all,looked at a job today.3 newly built brick chimneys back in august.House owners started noticing damp areas in the ceiling and upon investigation it seems the chimneys are extremely porous and a savage amount of water is coming in through the chimneys.An engineer was called and his report was that the wrong bricks were used"they were too porous.There are 2 lead trays in place where they are meant to be with weep holes.Engineer had no issue with the lead trays or soakers/flashing.Pictures were taken by the bricky at different stages of the project and all seems above board.Bricky was called back to look at the problem and accepted responsibility and gave the money he had earned for the job back.Now house owners want the chimneys plastered.I have two options 1 is to rendaid,scratch and finish with traditional s&c and option 2 is aquapanel fixed on with acrylic mushroom fixings and thin coat render system.My opinion is that either of these are good solutions to the problem but which would be the better 1 to go for.I really don't want to have a call back like the bricky
 
Hi all,looked at a job today.3 newly built brick chimneys back in august.House owners started noticing damp areas in the ceiling and upon investigation it seems the chimneys are extremely porous and a savage amount of water is coming in through the chimneys.An engineer was called and his report was that the wrong bricks were used"they were too porous.There are 2 lead trays in place where they are meant to be with weep holes.Engineer had no issue with the lead trays or soakers/flashing.Pictures were taken by the bricky at different stages of the project and all seems above board.Bricky was called back to look at the problem and accepted responsibility and gave the money he had earned for the job back.Now house owners want the chimneys plastered.I have two options 1 is to rendaid,scratch and finish with traditional s&c and option 2 is aquapanel fixed on with acrylic mushroom fixings and thin coat render system.My opinion is that either of these are good solutions to the problem but which would be the better 1 to go for.I really don't want to have a call back like the bricky
Any pics
 
I have this problem on a rented property. A good 25% of the bricks have become frost damaged so have become porous. After flaunching the stack and mushroom fitted to the pot I put sbr slurry on the brick with a sand and cement (waterproofed) scratch coat. Second coat sand and cement. Made sure the drip beads was below where the lead went into the joints.

On this stack being 100 years old wrapped expanded metal lathing around to give some stremgth but as your stacks are new maybe just mesh if they are not going to get hot.

A bit subject to gale damage are stacks so the mesh for anti- crack

just pay attention to how you join the render to the flaunching. Include it as part as if you can but the flaunching going into horizontal almost needs to more like concrete.
 
As rigsby says,if your doing it soon thin coat I wouldnt risk anyway,it's quite cold:RpS_thumbup:
 
Ya joining the render to the flaunch will be a tricky 1 so iv decided to rendaid all of the stack,tack on planed 3x1 (edge planed back at 45 degrees) to the top of the stack and leave approx 25mm-30mm extended above top row of bricks,fill with strong concrete mix,leave dry for a few days,remove 3x1's and now I have a nice strong edge to work up to all around. scratch at 4-1 with plasticiser and finish at 5-1-1 with a touch of waterproffer.Client doesn't want a big "ugly chimney cap" so I feel my only way to conquer the flaunch/render issue is this way.No pvc/aluminium angle beads allowed so has to be done freehand/timber lathes,(old style:))Although a drip bead is allowed around the bottom.
 
I find the best way for a chimney not to leak is,well dont have one..
however that is not always possible!!


What I do ask is ,upstand or flat against chimney ( leadwork I mean)..??
 
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