Cracked and Loose thermalite blocks. How do I fix this?

[mjgreen81]

Hi all,

I'm currently in the middle of a bathroom refurb on my late 1990s house It's my first time attempting a project of this size so I am learning as I go.

I've removed the dot and dab plasterboard from the external wall and I've found quite a large crack and a couple of the blocks under the window are quite loose and feel like I could pull them out if I tried.

I'm not too worried about the crack as from previously reading about these types of blocks, I do know that it is not particularly uncommon as the house moves.

However, I would like to try and repair this as much as possible and certainly try and resecure the loose blocks.

Can I get some advice for the best way to do this please?

Many thanks

 

[foxhole]

Maybe a small crack repair kit.

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[Wayners]

Have you watched the skill builder?

Remove blocks and replace if it bothers you

 

[mjgreen81]

Have you watched the skill builder?

Remove blocks and replace if it bothers you

Love this guy, but haven't seen this video. Will give it a watch

 

[noseall]

Pin a sheet of EML over it, then make sure you bridge the crack adequately with the sheet material (plasterboard, aquaboard etc). Plenty of dab on the EML.

You run the risk of cracking the remaining good blocks if you try and remove them. Especially if the compo is good gear. It's doable but you need a few power tools at your disposal to destroy the block from the centre out. We have had to tooth out loads of aerated blocks and it's a gamble.

 

[mjgreen81]

Pin a sheet of EML over it, then make sure you bridge the crack adequately with the sheet material (plasterboard, aquaboard etc). Plenty of dab on the EML.

You run the risk of cracking the remaining good blocks if you try and remove them. Especially if the compo is good gear. It's doable but you need a few power tools at your disposal to destroy the block from the centre out. We have had to tooth out loads of aerated blocks and it's a gamble.

Thanks. What about the ones directly under the window that seem loose already? Should I attempt to re-mortar them?

 

[noseall]

Thanks. What about the ones directly under the window that seem loose already? Should I attempt to re-mortar them?

Drive a slate perp' wedge in - vertically so you don't crack anymore blocks.

 

[mjgreen81]

Drive a slate perp' wedge in - vertically so you don't crack anymore blocks.

As a newbie to this, I'm not too sure what a slate perp wedge is.

Is this just a term for a wedge? I.e.i could just use a plastic packing wedge?

 

[noseall]

As a newbie to this, I'm not too sure what a slate perp wedge is.

Is this just a term for a wedge? I.e.i could just use a plastic packing wedge?

A Perp is the vertical mortar joint. Slate wedge or pack downwards vertically. Plastic will likely shatter

 

[^woody^]

While it's in that exposed condition, I'd be inclined to crack stich it.

Loose blocks by the cill could be refixed with a good tube adhesive. Also, gouge the cracks and seal them with the same adhesive.

 

[mjgreen81]

While it's in that exposed condition, I'd be inclined to crack stich it.

Loose blocks by the cill could be refixed with a good tube adhesive. Also, gouge the cracks and seal them with the same adhesive.

Thank you. Are you able to recommend a tube adhesive for this?

 

[noseall]

As a newbie to this, I'm not too sure what a slate perp wedge is.

Is this just a term for a wedge? I.e.i could just use a plastic packing wedge?

A Perp is the vertical mortar joint. Slate wedge or pack downwards vertically. Plastic will likely shatter

 

[^woody^]

Thank you. Are you able to recommend a tube adhesive for this?

For securing loose blocks, not the typical cheap white "no-nails" types, but any of the more premium solvent grab adhesives such as the green Gripfil.

Or if you want a product to also seal the cracked blocks with some flexibility, then a more premium polymer sealant/adhesive that normally sell for around £10. Or just cheap silicone for this, as it will be crack stitching that holds the wall and you just need a flexible product to seal it as mortar will crack again.

 

[mjgreen81]

For securing loose blocks, not the typical cheap white "no-nails" types, but any of the more premium solvent grab adhesives such as the green Gripfil.

Or if you want a product to also seal the cracked blocks with some flexibility, then a more premium polymer sealant/adhesive that normally sell for around £10. Or just cheap silicone for this, as it will be crack stitching that holds the wall and you just need a flexible product to seal it as mortar will crack again.

Thank you.

I've got a tube of Sika stixall in the garage. That should be ok right?

 

[^woody^]

Yes that should do