cracked thermalites

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pezzoworld

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Can anyone HELP!!!
I've had my lounge skimmed over but there are cracks appearing along a wall , I've looked and the thermalite blocks under the plaster are cracked
what can I do to stop the plaster keep cracking? any help
 
I'd hollow out the cracks and fill it with flexible filler if you've gone back to the block use eml over the crack
 
cracks

spunky said:
I'd hollow out the cracks and fill it with flexible filler if you've gone back to the block use eml over the crack
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Cheers Spunky
So you think by putting eml over the cracks will cure it as Ive tried putting filler in them and they keep reapearing Ididnt know if Ihad to chase off the plaster and reboard it the skim it again
 
What do you mean reboard it mate thought it was block?....if they keep coming back chase back to the block eml it then replaster it all you could put a tight coat of bonding over the wall and bed some acrylic mesh then reskim it if you didn't want the mess or wasn't sure of where the cracks are
 
cracks

Yes I understand what you are saying spunky eml, bonding with a mesh bedded in then skim coat .
what Iwas saying was
to stop the cracks reapearing I didnt kow if I had to remove all the plaster back to the blocks then put plaster board ontop of the blocks and a finishing skim to solve the problem
 
I dont want to really but I couldnt think of any other way to cure it as the thermalites are cracked so every time i filled the reapearing cracks they would just come back . are you sure by putting eml over the cracked blocks will work?
 
Bar nocking the wall down and redoing it yes how did you find out the blocks were cracked did you know before or after you hacked it off? What was on before was it sand cement ?
 
No I havent hacked all the plaster off but you can see the cracks in the thermalite blocks at the base of the plaster where the skirtings going to go
 
I'd either bed mesh into a coat of bonding or go back to the block and eml or like you say along as it hasn't blown you could dab the wall I'd just go straight over the existing
 
spunky
what do you mean put the boards over existing plaster.
Ive got to admit i like the idea of eml and mesh in the bond coat i just hope it works
 
pezzoworld said:
Hi Kemp
The thermalites are on a internal wall theres no cracking on the outside walls so there's no movement there
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No but by the sound of things there's movement in the thermalites, you need to address this first or it will always crack, has the plaster blown from above/below the crack or is it bonded to the blocks, if its bonded you have movement, subsidence, if it sounds hollow between the plaster and the block work then the backing plaster has blown and subsidence does not cause that type of failure, was the wall cracked before ?
 
take it back to the blocks , eml on, then bonding and skimming coat , just make sure the eml is on flat and well secured, i have done this a few times without further troubles.
 
i would just use collated galvanised nails, but it depends on the area, you could plug and screw using washers , but i think the nails would hold it.
 
gordo said:
take it back to the blocks , eml on, then bonding and skimming coat , just make sure the eml is on flat and well secured, i have done this a few times without further troubles.
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Don't use bonding on Thermalites even over EML, Bonding is only for low suction backgrounds so use Hardwall unless you're going to line the wall with building paper before fixing the EML (IMO a good idea).

pezzoworld said:
cheers gordo
i thought of those u shaped galv nails ,are they the same as youve said collated nails
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I haven't a clue what he means by collated nails in this scenario but just use 40mm extra large headed clout nails.

If the wall was originally floated with S&C this could be the cause of the blocks cracking if the S&C was to strong, aerated blocks require a weaker mix.
 
pezzoworld said:
Hi Kemp
The thermalites are on a internal wall theres no cracking on the outside walls so theres no movement there
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Your bedroom floor joists sit on the internal wall and if there are no wall ties between inner and outer skin of brick you may well have movement on the inside but no evidence of it on the outside, :flapper:
 
I think you mean clout nails not collated? Clout nails will be fine. 100mm wide EML, make sure it goes well past the crack all the way around, hardwall then skim as been said, I do crack patches at least once a week and 99% of the time we do it this way. The other way is to use heli bars and 2 part resin which we use when they are subsidence cracks.
 
cheers beddy
it sounds like eml is the way to go and im glad ive been told to use hardwall instead of bonding
you know these heli bars do you just put themat equal spaces up the wall in line with the crack and how long do you make the bars as in length?
 
youre supposed to put them above and below the crack, 200mm passed either side. they tell us to rake out the crack, chuck a load of resin in and put the bars in horizontally which wont do s**t. also they are starting to use this method instead of underpinning. how that works i dont know...
 
The cracked blocks could come from when the wall was built, it is usually caused by the compo being a too strong mix and excessive shrinkage takes place
 
beddy has described how we do crack repairs for insurance work carried out under structual engineers.
as the crack is vertical it is called thermal cracking.
it would be safest to sub this work out to some one who is experienced in this type of work.
 
beddy said:
a load of resin in and put the bars in horizontally which wont do s**t. also they are starting to use this method instead of underpinning. how that works i dont know...
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underpinning costs thousands ,they know it is alot cheaper to do crack repairs.
 
Why not batten out the wall straight over the old cracked plaster and board and skim? Save all the dust and mess of hacking off.
 
Just dot and dab the bloody thing. No need for eml, hacking off, mesh or any of that bollox.

Board it and skim.
 
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