More chimney woes

[Irisheyes]

Hi all,
I’ve had a roofer up a few times sorting out a damp chimney on my 1903 terrace house. It was the leading, then between the bricks bad soft cement so that was replaced. I’ve asked both of them if it’s possible to paint the chimney in waterproof paint to seal the bricks but both were against it. Why? The chimney is active from one log burner and the other is open with vented pot.

I’m getting really sick of this!!
Thanks for your help.

 

[Jacob]

Hi all,
I’ve had a roofer up a few times sorting out a damp chimney on my 1903 terrace house. It was the leading, then between the bricks bad soft cement so that was replaced. I’ve asked both of them if it’s possible to paint the chimney in waterproof paint to seal the bricks but both were against it. Why? The chimney is active from one log burner and the other is open with vented pot.

I’m getting really sick of this!!
Thanks for your help.

Log burner not good in an open flue as it doesn't generate the draught of an open fire. Needs lining - twin wall insulated stainless, and capping to deflect rain water.
Open chimney needs capping too (open but deflecting rainwater) and open at the bottom to allow draught through.
OTOH if the masonry was very damp it may just be taking a long time to dry out.

 

[Irisheyes]

Log burner not good in an open flue as it doesn't generate the draught of an open fire. Needs lining - twin wall insulated stainless, and capping to deflect rain water.
Open chimney needs capping too (open but deflecting rainwater) and open at the bottom to allow draught through.
OTOH if the masonry was very damp it may just be taking a long time to dry out.

Thank you . The log burner was fitted with all that so it should be ok, and the pots are capped too.
Do you know why there is a reluctance to make the bricks more waterproof?

 

[Jacob]

Thank you . The log burner was fitted with all that so it should be ok, and the pots are capped too.
Do you know why there is a reluctance to make the bricks more waterproof?

"Waterproofing" can sometimes keep moisture in and cause problems of its own.

 

[Old.bodger]

This is the correct lead detail. Without the lead tray you will struggle, especially with some brick types. Coating bricks can trap moisture. Mortar……Portland or lime ?

 

[Sachakins]

Brickwork, specially old bricks need to breath, trapping moisture into bricks can, if it freezes cause brick to crumble or even burst.

 

[Jaydee]

I’m no expert, but I have used a product called storm dry. It’s a coating that paints on and soaks in to the bricks and mortar. Once soaked in it’s invisible and It breathes. It won’t let water in, but will let water vapour out. I used it on my garage workshop single skin walls to waterproof it. When you run a hose over it the water just beads up and runs off. You can put it on new mortar as it will allow it to slowly dry out. I believe it’s used on heritage projects.
The skill builder YouTube channel did a little review on it. Also check out their web site. http://www.stormdry.com/