A VERY wet Welsh house - all from cement render - not rising damp!

[@mikeenglish7063]

Yep cement isn't particularly good for an older house.. ...... However the simple fact is that the render appears to go down past ground level. That's why it's wet.

[@isctony]

Would love to have an update on this one in the future Peter. Fantastic videos and great insight to the problems, thank you.

[@WarmDryHome]

It was finally re-rendered in lime after about a year of drying out. Terrible job to do, as the walls were soaked, and took a long time to start to dry - but its fine now, with lime internally and externally...

[@steveharrison1048]

i'm so glad i've found someone else who got mortar out that wet as i've just found some the same in my house which has been cement rendered and is 150 years old so is constructed with lime mortar

[@WarmDryHome]

Hope its dried out a bit now - it takes time and patience!

[@johndillon5290]

Sorry Peter, are you suggesting that cement rendering on external walls in a house is bad, or just in certain cases? If so, what is the alternative to cement? Thank you

[@whitacrebespoke]

Glad you dog was ok. Have two collies myself that often accompany me to work.

[@WarmDryHome]

Lost her in the end Adam - traumatic. My best mate for 14 years. My friends are trying to get me to find another one. It'll probably happen - but I need a bit of time..

[@whitacrebespoke]

So sorry to her you lost her. I took me a long while when I lost my first collie. I decided life was better with collies in in that was 7 years ago in August now have two including the young home bred dog.

[@mikeenglish7063]

The render has covered up shit brickwork. That should have been repaired. Repointed . Preferably with lime . It obviously had render applied over the top to hide it all.

[@frankief7111]

Not sure what you define as rising damp but isn't water from the elevated ground being sucked in and up the wall by the render? Is the process of damp rising up the render spreading across into the mortar not rising damp? For this to affect the inside of the house the cavity must also be compromised or more likely there is no cavity (solid wall). As long as the ground is flush to the wall it will be difficult to make a permanent solution

[@WarmDryHome]

Yes - not rising - in that case it is penetrating. There is no cavity here. If the entire wall was totally breathable - it would be dry. Moisture from the ground is minimal really as long as it can escape.

[@MT_T991]

I've got a lovely example of cement render damage on a timber frame house the render is now partly structural. it's destroyed to soleplate which looks good and dry inside. the reason it's dry is the timber is so rotten it doesn't touch the brick plinth. if you have an email I'll send you some details and the repair pictures before and after

[@WarmDryHome]

Sounds good... [e-mail] ...

[@freedomfighter84]

What was the source of the moisture in the wall? If you remove the render and install new render wouldn't the same thing happen unless different measures taken into place? Would be possible to hack off plaster from inside the house to aid drying of bricks? Plaster could be salt contaminated anyway?

[@WarmDryHome]

Moisture is trapped by render that is impervious - there is water in the air all the time as a gas - it diffuses through everything, but when the wall gets cold - ie cold wind blowing round the corner or near the ground, it then condenses within the wall and makes it wet. Fine if there is lime - it can evaporate - but put cement or gypsum on the wall and it is trapped and cannot then get out. Taking plaster off internally would help - but wall dries at about 1 inch per three months - so a long drying time. Plaster will be salty yes - so much water that the lime mortar and bricks themselves are almost dissolving - so plenty of salts forming.

[@JasperJohnD]

Poor dog. Glad she's up and about

[@WarmDryHome]

Thanks - we did lose her in the end - but that's another story - 14 - so had a half decent run - I'm going to have to get another - can't stand being without her..

[@maryroberts9572]

Have you ever come across true raising damp?

[@WarmDryHome]

No - never - in 25 years of surveying and working with old houses, not one case - it does not exist. Complete fraud. It's a figment of the fraudulent minds of the injection damp proofing wallys.

[@iamaGod357]

Why do all houses have a DPC then?

[@aaronrothwell9026]

I understand that the cement render is trapping moisture in, but what I can't get my head around is how the damp got in there in the first place as the render has stopped water penetrating.

[@WarmDryHome]

Its not penetrating to start with - Moisture is trapped by render that is impervious - there is water in the air all the time as a gas - it diffuses through everything, but when the wall gets cold - ie cold wind blowing round the corner or near the ground, it then condenses within the wall and makes it wet. Basically fog forms in the wall. Fine if there is lime - it can evaporate - but put cement or gypsum on the wall and it is trapped and cannot then get out. Taking plaster off internally would help - but wall dries at about 1 inch per three months - so a long drying time. Plaster will be salty yes - so much water that the lime mortar and bricks themselves are almost dissolving - so plenty of salts forming. Cold wall = cold wind blowing round the corner in the video.. Typical example.

[@aaronrothwell9026]

+Peter Ward wind blows round every house, so does that mean modern houses with render systems fail as well? because your explanation states that the cold air as a gas condensates in the wall, which then can't escape through modern render/plaster. surely this is also the case with modern buildings then? I'm not trying to be argumentative, I just don't understand the logic.

[@WarmDryHome]

You are right - modern render systems fail all the time. Why are they rebuilding motorway bridges all the time - because interstitial condensation builds up over the years and rots the iron re-bars. We are far better off with breathable materials that allow moisture to move freely, rather than trapping. Modern houses get same problem - but have cavity walls, and as long as those are ventilated, you never get to see the effects. Block the cavity, and sit back and watch all hell break loose. Why do you think building control is so hot about not allowing rubble in cavities...?

[@WarmDryHome]

You are right - modern render systems fail all the time. Why are they rebuilding motorway bridges all the time - because interstitial condensation builds up over the years and rots the iron re-bars. We are far better off with breathable materials that allow moisture to move freely, rather than trapping. Modern houses get same problem - but have cavity walls, and as long as those are ventilated, you never get to see the effects. Block the cavity, and sit back and watch all hell break loose. Why do you think building control is so hot about not allowing rubble in cavities...?

[@welshdragon010]

Hi Peter We are currently doing the same to our gable (welsh house near swansea). We have high humidity inside and house can be cold. I';ve heard of lime render and when we come to have the front re pointed it will be lime. What sort of render would you advocate in a similar position? Lime? And once rendered in lime would you use a lime wash paint? Thanks Andrew

[@WarmDryHome]

Must be lime - but maybe not render - could just re-point in lime. Must use limewash - even the silicate paints are not really breathable.

[@londontrada]

Did you take it all off or just up to the damp part?

[@WarmDryHome]

Everything in this case. Often the only sensible thing. A lot of the time, the damp wallies have only done the obligatory meter up the wall, so we take that off, and put the original material back - and the wall dries out straight away.

[@FreeWareFrolics]

Hi, my internal plaster started to peel off/disintegrate and I have been told my house has trapped moisture but only in the recently built extension where the issue is. I have been quoted 13k which I do not have. As such I was wondering, can I remove the render myself and repoint it myself, or will it risk doing more harm than good? Also since the bricks are wet, do I have to protect the stripped brickwork from rain?

[@WarmDryHome]

Strange as recently built extension. Doesnt make sense if modern build. More likely condensation from too much moisture. Before you do too much and spend any money - check ground levels are below internal floor., check drains clear, make sure kitchen is well ventilated, bathrooms vented, good airflow through house. You don't need ANY damp proofing or plaster / render. Can send some pics to [e-mail] and I'll have a look if like - but I think it will be ventilation as main cause. Pete

[@kathcole2128]

shouldnt there be a bell cast bead six inch above ground level?

[@WarmDryHome]

Yes - but obviously here ground was way too high anyway. Biggest issue was the cement - death to any solid walled house..

[@DougEDoug-om8ie]

Very interesting. What did you end up doing to the damaged brickwork in the end? Did you re-render?

[@WarmDryHome]

It was fully re-rendered in lime - took over a year to dry out first.

[@trishbeebe3796]

Peter - I would so like to get in touch with you regards advice on a restoration project. I live in Bulgaria and there is a "Major" lack of info here on how to work with these old traditionally built homes. Lots of cowboy builders who all want to put XPS over and under everything along with spray foam!!! and nobody with traditional experience. I have massive ceiling oak beams with woodworm , damp, cement render over stone and adobe bricks and mold on the mud floors! I need help - badly. Please, may I contact you? Hey, Could I possibly interest you in a visit to Bulgaria? Wonderful place to visit :)

[@WarmDryHome]

Hi Trish - can you email me: [e-mail] and we'll see what can be done... Sounds like a beautiful building - there ARE builders out there - but I think you looking in the wrong place perhaps.. Anyway - email me some details and we'll have a look.. Pete

[@trishbeebe3796]

Peter, my deep appreciation for your kind offfer. will mail you soon - rushing out with the camera to take some pics to send you !

[@trishbeebe3796]

Thanks Peter - have mailed you directly.

[@WarmDryHome]

Got your email - will get to it as soon as I can!!!

[@marksmith8663]

Hi PeterI have a end terraced house over 100 years old and the kitchen single story wall is rendered. (with cement) I took a patch off and put sealant in the mortar a year ago. However the wall is saturated. Would you recommend lime rendering the wall. If so what is in it? Is it just sand and lime?

[@WarmDryHome]

I'd rake out the brick first, with a chisel - NOT angle grinder as it damages the bricks and allows frassing. Remove any sealer! Then re-point in lime - but NOT builders lime.. Its hydraulic lime, not hydrated - a 3:1 mix of coarse, gritty sharp sand with 1 lime - usually NHL 3.5 hydraulic - can get form most big builders merchants - but if not - Ty Mawr do it - not sure where you are.

[@marksmith8663]

ok thanks I live in cheshire , will search for NHL 3.5 hydraulic in this area might to have it delivered , a most only sell builder lime round here . is NHL 3.5 lime ok to render with as well as for re pointing ?