Patches on new plaster

[Alastairreid]

Well spotted Benny.

btw ignore bobarse, theres something wrong with him.

 

[bobasd]

Next floors whether loft or first floor or any woodwork will burn - and for you to deny that wood burns is nonsense.
To deny the Regs where fire is concerned is gross nonsense - and maybe a little stupidity.

Does the idea of "sand and lime on brick" surprise you or even excite you? Do you really need two question marks & an exclamation mark to demonstrate your ignorance? I'm afraid it must.

 

[bobasd]

Next floors whether loft or first floor or any woodwork will burn - and for you to deny that wood burns is nonsense.
To deny the Regs where fire is concerned is gross nonsense - and maybe a little stupidity.

Does the idea of "sand and lime on brick" surprise you or even excite you? Do you really need two question marks & an exclamation mark to demonstrate your ignorance? I'm afraid it must.

 

[dontbelieveawordofit]

well lets just remove everything that’s wood . good idea! oops there’s that exclamation mark again.
could always screw corrugated asbestos over it all . and paint it with high temperature paint .

 

[Alastairreid]

Does the idea of "sand and lime on brick" surprise you or even excite you?

...

 

[Alastairreid]

dont use plasterboard or batten and board.
batten and board, like D&D that has "venting", also provides a chute behind the boatds for flame and esp smoke to shoot up to the next floor

Kit, timber frame buildings.

 

[bobasd]

OP,
you have an external chimney breast, & its very possible that chemicals from the flues in that chimney breast were and are penetrating what most probably is a single brick flue wall.
Gypsum plaster was used on the bedroom walls - bad plasterer.
All flues will need sweeping and the stack, flaunching and flashing will need inspecting.
There's no signs of any fireplace having been on that wall - its an irrelevancy anyway.

All the affected walls in the bedroom will need plaster hacking off back to brick, and rendering with sand & lime.
Dont use any gypsum plaster.

 

[Muj]

are there any chimneypots? How many?

How many fireplaces were there downstairs?

It looks to me wide enough to have had two flues.

Sometimes housebuilders will build things, such as a chimney, but make you pay more if you want extras, such as a fireplace, added.

If there are flues that are not ventilated top and bottom, this will cause condensation inside. It is easily remedied by adding an airbrick near the top and bottom of each flue.

Sometimes homeowners close off airbricks.

You may need to get up high to see if there is good lead flashing preventing rain off the roof running onto the brickwork.

Look at neighbouring houses built in similar style

I think there are two chimney pots on each chimney, I have two fireplaces both with external chimney.

I’ve had a look and can see air bricks on the house near the chimney but none on the chimney itself.

see pics below (The first chimney is on the offending room). Above that is loft space

 

[Muj]

OP,
you have an external chimney breast, & its very possible that chemicals from the flues in that chimney breast were and are penetrating what most probably is a single brick flue wall.
Gypsum plaster was used on the bedroom walls - bad plasterer.
All flues will need sweeping and the stack, flaunching and flashing will need inspecting.
There's no signs of any fireplace having been on that wall - its an irrelevancy anyway.

All the affected walls in the bedroom will need plaster hacking off back to brick, and rendering with sand & lime.
Dont use any gypsum plaster.

There’s me thinking gypsum plaster was good!

 

[dontbelieveawordofit]

chemicals ? if that was the case, assuming you mean tar deposits from coal or wood burned previously , then that combined with the presence of moisture would cause heavy yellow staining not hygroscopic salt.

 

[Muj]

The patches feel colder than other parts of the wall, not sure if that information helps at all

 

[dontbelieveawordofit]

ok so judging by the height of those there will certainly have been fireplaces upstairs when the place was built , so as stated previously there should be an air brick or vent present in the wall.
given the spread of dark / damp areas though it probably wont cure the whole problem and certainly wont stop salt situation.

 

[JohnD]

I think there are two chimney pots on each chimney, I have two fireplaces both with external chimney.

I’ve had a look and can see air bricks on the house near the chimney but none on the chimney itself.

The chimney pots will ventilate the flues at the top; there should be ventilation at the bottom as well, to give airflow. An open fireplace will do it, or (usually) an airbrick is let in when a disused fireplace is bricked up. In some cases, a chimney that has been dug out can be ventilated out of the void under the floor.

As noted above, water may be getting in from bad flashing or other defects, and rain falling down. Lack of ventilation will prevent them drying out quickly. Soot and salts in a chimney can be hydroscopic and harbour damp. IME damp in a formerly used flue shows itself by brown stains on the plaster, from the tar and soot. Flue that have never been used are less trouble, but can still be damp. The damp on your wall does seem very widespread, I wonder if there is a guttering problem.

If you never expect to use your fireplaces again, you might consider having the chimneystacks taken down or reduced, and the roof/gutter/flashing tidied up.

A experienced local roofer, by personal recommendation, could take a look and notice common defects.

 

[JohnD]

update

looking again at your photos, I see a build up of rubbish, moss (and perhaps grassy weeds) where the chimneys meet the roof, this will harbour damp and may bridge the flashing.

A sign of long-term neglect.

There are also a couple of slipped tiles that your roofer can replace.

 

[Muj]

ok so judging by the height of those there will certainly have been fireplaces upstairs when the place was built , so as stated previously there should be an air brick or vent present in the wall.
given the spread of dark / damp areas though it probably wont cure the whole problem and certainly wont stop salt situation.

The chimney pots will ventilate the flues at the top; there should be ventilation at the bottom as well, to give airflow. An open fireplace will do it, or (usually) an airbrick is let in when a disused fireplace is bricked up. In some cases, a chimney that has been dug out can be ventilated out of the void under the floor.

As noted above, water may be getting in from bad flashing or other defects, and rain falling down. Lack of ventilation will prevent them drying out quickly. Soot and salts in a chimney can be hydroscopic and harbour damp. IME damp in a formerly used flue shows itself by brown stains on the plaster, from the tar and soot. Flue that have never been used are less trouble, but can still be damp. The damp on your wall does seem very widespread, I wonder if there is a guttering problem.

If you never expect to use your fireplaces again, you might consider having the chimneystacks taken down or reduced, and the roof/gutter/flashing tidied up.

A experienced local roofer, by personal recommendation, could take a look and notice common defects.

I’ll speak to a roofer to see if the guttering needs sorting and if an airbrick can be added both towards the top and bottom.

Does that mean I would still need to go back to brick internally ?