sealing a chimney help

[kev1744]

hi all,
hope someone can help me. noticed i have less chimney pots than my neighbour (semi detached property exactly the same etc) went on roof to check and saw that 2 of my flues had been capped off with mortar. one of these has collapsed and im assuming needs sealing off again. any ideas as to best way to do this?

the house is about 60 years old and the 2 sealed flues were for the fireplaces in the bedrooms (long sealed off) i was thinking of just placing a couple of air bricks on top and then putting a flat slab on top of that to keep rain out etc. will this work?

 

[Alastairreid]

A couple of air bricks per vent/flue and will be fine as long as it is also vented at low level if the fireplaces are sealed off.

 

[kev1744]

sounds like another trip onto the roof for me then
just out of interest my house has 2 chimney breasts with fireplaces in 2 downstairs rooms. the bedrooms had fireplaces at some stage and have been sealed off.
ive attached a sketch of the chimney layout....can anyone tell me if each fireplace has its own flue? or do the living room and bedroom one share a flue and the dining room and bedroom 2 share?
im a little confused as to how it works

hmm not sure how this album thing works either hopefully my sketch is there for all to see

 

[Alastairreid]

The vents would be separated by bridges.

View media item 36220

 

[kev1744]

Ok now I'm lost what are bridges? Where do they go? Can I still get the chimney swept without damaging them? Sorry I know lots of questions but not heard of bridges before

 

[Alastairreid]

You have 4 vents on your chimneystack each serving a different fire, the vents are separated with a course of bricks called bridges.

 

[kev1744]

ah i think i see, so i take it these bridges separate the flues so smoke and debris cant go from one to the other?
in which case i guess i should try and get the collapsed one capped off sooner rather than later. as it is now stuff can fall down it and i would have no way of clearing it as the fireplace has been plastered over

 

[Alastairreid]

You got the idea.

Instead of punching through the chimneyhead it may be easier for you to install vented terminals!

Untitled

• Alastairreid
• 17 Jul 2009
• 20

designed to sit on top of redundant vents to maintain airflow in the flue. can be picked up in salvage yards for around a tenner each.
They are called elephants feet or terracotta vent terminals if you want to be technical

 

[kev1744]

dont think i will have a problem punching through the chimney head...there is no chimney pot on it and it looks like years ago they just capped it off with a mound of mortar, which has fallen in so all there is now is a hole.
idea is to build a one course "wall" around the hole out of air bricks or engineers bricks, then mortar a small paving slab on top of that

again ive done a quick sketch hopefully it explains it...

i am assuming the chimney head is the stack bit? (the brick bit that the chimney pots sit on?)