Chimneys in old houses - why they are wet and what to do

[@hisroyalblueness]

Writing as a bloke with a damp chimney looking for enlightenment, I must say that I really appreciated the no-nonsense clear descriptions and common sense. I’ve subscribed accordingly, thank you.

[@gonnfishy2987]

Videos like this help me feel so lucky I’ve only lived with well-kept chimneys or ones the family built themselves. So many things to go wrong! Look after your chimneys, in return they won’t burn you, raze you or choke you❤

[@oak16v]

What product, if any, do you put back on the wall after removing the paint, letting the brickwork dry and lime mortaring?

[@choc_chip]

Hi Peter, thanks for this video. I'm an Edwardian end-terrace owner on a low income. I believe my house is an absolute case in point (pardon the pun). I had the roof replaced 3 years ago, but the chimney is still dripping and it turns out the roofer didn't cap it. Now the upstairs chimney breast is so damp it's making me choke to sleep in there, but a recent quote to cap/repoint the chimney and repair some guttering was £1200. This seems extortionate to me (no scaffolding). Would you be able to suggest the kind of costs involved in improving cases like these? And does it have to be all or nothing? Many thanks.

[@Hew.Jarsol]

Thanks. What can we use to remove the paint with, and Inc on sandstone?

[@okafka5446]

What method would you recommend to take all the paint off?

[@plummetplum]

I'm about the rebuild my front garden wall and a section will be against my house. How would you recommend I prevent damp transferring to house. Leave a gap? Join in with a mortar bed? DPC?

[@WarmDryHome]

You need either a physical gap, or if you are using lime mortar, you could loosely pack the join with a hot lime mortar that will wick any moisture away. Ideally build the wall in lime, and you'll have very few problems.

[@hopclang9409]

@@WarmDryHome no Wally that is just stupid. Of course he wont use lime on a garden wall

[@elliottdebell7783]

How would you get the paint off. I have the same problem.

[@WarmDryHome]

2 main processes in UK - Doff and Torq - but low pressure sandblasting at aroud 40 psi can do it - dont want to damage bricks though

[@heartland96a]

Are there any legal actions against these fraudulent damp proof businesses?

[@ijl66]

Easy to solve. But very, very expensive!

[@CurvedSlightly]

Not really, remove paint, remove plaster. I bet the damp proofing would cost more.

[@ijl66]

It would cost a small fortune for the scaffolding alone, never mind the rest of the job!

[@beerd6706]

@@ijl66 as the other guy said, not really. A scaffold around an entire house can be done (at least where I'm from) for around £1,000. Not really a small fortune considering the damage it could cause not having it done in my opinion. 🤘

[@sunfall1407]

Hi, does the salt come from the clay used to make the bricks, similar to efflorescence?

[@kraigjohnstone3217]

Salt comes from rain water

[@hopclang9409]

@@kraigjohnstone3217 haha rain oh shit, who told you that?

[@hopclang9409]

@@kraigjohnstone3217 yeah cause the sea isnt getting more salty as rain is spreading salt of people's houses !!! haha

[@Drdoombrain]

Will the structural be good after repointing?

[@Cluedup2399]

Hello peter im a plasterer myself are you basically saying gypsum and sand and cement is ruining old buildings

[@benmjt]

Yes

[@Cluedup2399]

@@benmjt hi peter ive never went into the damp proofing side of things but i have recently been working for a housing association and there asking me to use the quite new to the market delta lagh what do you think of this personally i have always thought it was a load of bollocks it really interest me your side of things

[@LiamGrubby]

Lime plaster should be used. Cement and gypsum and non vapour permeable.

[@rhysevans7903]

Can use a limelight renovation base and top coat,,it's modern lime easy to use and let's the walls breath

[@jamiemclaughlin4270]

Hi Pete, what’s the best form of removal of paint on something like this chimney stack etc without causing to much damage.. Also is pliolite paint recommended on lime brickwork??? Many thanks

[@WarmDryHome]

Low pressure hot water systems like Doff and Torq are best. Pliolite is horrible stuff - plastic coatings. dont use.. On limewash, use limewash.

[@terencebroderick2682]

Hello peter I’ve been recently watching your posts and other guys as well. Finding it interesting and I’m curious about your lime mortar I recently rebuilt the top of my chimney stack and I used a 4/1/1 mix of building sand , cement and hydrated lime . I take this is not what you would call lime mortar ? I realise I could google it for an answer but that would not give me the opinion of an experienced guy Thanks in advance Terry

[@WarmDryHome]

No its not - thats just mortar plasticiser and useless. You need 2.5 times sharp gritty sand, 1 of Calbux 90 hot lime - which should be wetted a little with the sand .. 3 to 1 is a weaker mix, 2.5 to 1 stronger. You cant use ANY portland cement - get rid!

[@terencebroderick2682]

Peter Ward I am bricking u a window at my daughters house at the moment in Surrey and I placed the blocks last week . I’m going back next week to lay the facing bricks .then I will hang a boiler on the inside of the wall . The boiler is being repositioned because of a planned extension. This is nothing to do with damp problems but I’m just interested. I have worked in the building trade all my life and didn’t realise the significance of the lime and it’s effect . Thanks for your prompt reply peter

[@zbigniewpilipczuk8864]

@@WarmDryHome hot lime mixed with water will react to hydrated lime anyway, why then it is so important to use burnt lime. Historically, and I remember that time, before starting any new bilding burnt lime was buried for at least few weeks before it was used in mortar. I need to check the difference in setting time.

[@MostynWitham]

Why not say where the salt originated from?

[@benmjt]

Burning fires

[@hopclang9409]

@@benmjt haha no fires haha, salt comes from the sand you Wally

[@beerd6706]

@@hopclang9409 are you 12 years old? You end every comment by calling someone a wally as if to attempt (rather poorly) to instigate a debate for no reason? You wally 🙄😂

[@MarcGray1990]

what point in time did they switch to cement based mortar... I have a 1938 semi detached and I'm fairly certain that's all cement mortar from original?

[@jonesconrad1]

around that time, really picked up second world war.

[@stephenmitchell1270]

They still often use hydrated lime in modern cement based mortars to improve it's performance / workability and durability. But with older properties that used lime mortar it is best just to stick with that when remedying an issue or it will cause more problems down the line.

[@Drdoombrain]

Same

[@Bowden999]

I have white fur looking powdery stuff on my chimney and it has new plaster board what is visibly wet to the touch, is the white salts? It's effecting items in a metal tool chest in the opposite side of the breast in the kitchen?

[@benmjt]

Sounds like salts yes.

[@willkndy]

Hi Peter, i've blocked up my chimney which was built with concrete cavity blocks in the 70s, the chimney breast is shared with my neighbour so its not on an exterior wall. I stuffed a plastic bag filled with rock wool up into the chimney and had it blocked up and plastered over with gypsum plaster. Theres now no vent at the bottom of the chimney stack. That was about 6 months ago and I've had no problems yet, do you expect this will give me problems with damp in future ? Thanks.

[@matilda2]

I'm about to do the same. Would value Peter's opinion

[@1petrofski]

Yes stopping air flow will most likely result in condensation on walls causing damp

[@derekmulready1523]

Dublin Corporation insisted that I put a vent into a blocked upstairs room fireplace to prevent future dampness. That was in 1984. So far no problem

[@nodriveasusephotos8019]

caused by painting or just old age? when you say re-build do you meant rake out and point with lime mortar?

[@jamesgraham4392]

I think Peter is referring to the top section of the stack that needs to be disassembled because of the the lean on the stack, just raking out and pointing alone wouldn't straighten it out and would still be unsafe, so a full rebuild of the top section using the original brick and re bedding them with lime mortar would straighten out the stack making it structurally sound and looking grand once again! (And dry).

[@hopclang9409]

@@jamesgraham4392 no you can rebuild with sand and cement. No new chimneys are built with lime. Come on Wally wake up

[@medwsc123]

Mine is, just rebuilt in NHL5 👍