How to repair chimney top (Ed.)

[davewain]

Hi All

This is my first time on the site and looking forward to it and some help please?

I have been in loftspace and chimney breast is very wet and its damaged to plaster and ceiling to daughters bedroom underneath.

Upon going up on the roof to look at the chimney there looks like a hole in the mortar but the flue also looks like it may let water in? The make looks like URASTONE and reading up online looks asbestos and very old, should i replace it? take off all the moss? mortar back in the holes? repoint the stack? Not sure where the water is getting it but want to make it rubust whilst scaffold is up.

Any suggestios are welcome ?

Many Thanks

Dave

 

[gas112]

i Would be looking more closely at the lead flashing to the tiles than possible ingress through that hole

 

[JohnD]

Is the flue still in use, or likely to get used again?

It is not likely for a gas boiler, unless you have a very old one, it may have been for a gas fire (rarely used now)

 

[davewain]

Hi both,

Thanks for commenting

Great shout - my roofer is going to put a bigger flashing on to the backside of the chimney as it looks shallow he has said and come away in places. Also a small moss garden between the tile and chimney

Yes we use a very old warm air heating system and the flue is still in use.

Thanks

Dave

 

[JohnD]

I'd be inclined to remove the perished mortar and any damaged bricks, and retop it with a resistant engineering brick and new lead flashing.

These bricks are relatively expensive, but you only need a few, and they will last longer than the house.

I don't know what sort of terminal or chimneypot you need. What appliance uses it?

 

[davewain]

Thanks i will do this and change the top two courses to engineering brick

How would i seal from the brick to the flue? do i need a pressed metal surround or plastic ?

The current blob of mortar looks rubbish

The whole house warm heating system is ran off the boiler. It is very old but works really well and pushes hot air through grilles in each room

thanks

 

[JohnD]

Do you mean there is a metal flue liner inside the chimney?

 

[davewain]

no sorry i meant when i change to engineering brick what happens to the top of the chimney around the flue. Currently its mortar with big hole in

 

[JohnD]

I don't know modern procedure, somebody will. It used to be done with bits of slate and mortar.

 

[ree]

OP,
As you seem to be proposing: remove the top two or three courses and flaunching, & re-build with engineering brick and new flaunching.
Why not re-new with a chimney pot & a redundant flue venting cowl?
Over the hole, the new pot would sit on broken slates.

The whole c/stack beds and perps need grinding out to 25mm depth, & re-pointing.
Why not post pics showing the flashing on all four sides of the stack?
It sounds as if the back gutter might need re-building? Just messing with one piece of flashing wont be good enough.
Have you probed the rafters in the loft looking for rot?

 

[gas112]

that terminal looks like a 4 inch one you would use a clamping plate on top of brickwork then cement

4" INCH / 100MM FLUE TERMINAL PLATE & CLAMP SET | eBay

Screw the tow nuts and bolts togethers to hold the flue liner securely. A two piece aluminium plate used to support the liner at the top of the stack. SCREW HOLE POSITION MAY BE DIFFERENT. OVERALL SIZE IS 305MM X 270MM.

www.ebay.co.uk

 

[gas112]

OP,
As you seem to be proposing: remove the top two or three courses and flaunching, & re-build with engineering brick and new flaunching.
Why not re-new with a chimney pot & a redundant flue venting cowl?
Over the hole, the new pot would sit on broken slates.

Presumably, the fireplace appliance and SS flue liner are now redundant - so, if it is a SS liner, remove it from the hole at the top of the chimney stack. Then have the flue swept.
The whole c/stack beds and perps need grinding out to 25mm depth, & re-pointing.
Why not post pics showing the flashing on all four sides of the stack?
It sounds as if the back gutter might need re-building? Just messing with one piece of flashing wont be good enough.
Have you probed the rafters in the loft looking for rot?

he said flue still in use

 

[davewain]

Hi I will take some more pictures but the boiler and flue is still in use.

Thanks