internal wall behind the rad has popped and cracked.

[frustin]

Given that the wall on either side of where the rad was hanging is sound and solid, I can only think that the heat is the cause. Most of the other radiators upstairs have the same issue.

I cant NOT have radiators so I was thinking of adding silver foil reflectors on the wall before rehanging.

I'm thinking of buying this stuff. Will that be ok or do i need NHL 2? Once it's gone off, i need to redrill to rehang the radiator. Will this hold the weight?

 

[paulc]

Had a dickens of a job hanging one particularly large radiator here on one solid brick wall. Sod's law dictated that one fixing went in to a crappy lime mortar joint, and another just on the edge of a brick and punched through in to a void (bricks here are laid frog down, so voids are inevitable). Suffice to say, the supplied fixings pulled out as soon as any load was applied. Switched to expanding rawbolts, but they didn't last long either.
Ended up pumping the holes full of resin before inserting the rawbolts. Those little puppies are not coming out again unless the wall is demolished

Looking at your wall, I suspect that expanding plastic wall plugs had been used. Judging by the way the plaster has popped, the wall plugs had only been pushed in far enough to be flush with the wall - When the screw was screwed in, the bulk of the "grip" would have been on plaster rather than solid brick. Wall plugs need to be pressed in below the level of plaster so that they expand as much as possible in solid brick. I also suspect that who ever drilled the holes hit a mortar joint so had to drill a second hole slightly higher.
The traditional way would be to hammer some wooden pegs in to the holes and screw your brackets to the wall. Depending on the size of radiator, that might work for a while.
I'd go for the belt & braces fix - Drill the holes a little deeper to make sure you're going in to solid brick. Pump some resin in, and then insert wall bolts (or studs). You need to be quick tightening everything up as you only have minutes before the resin hardens. Tip. Smear some grease on to the bolts (not the expanding shell), then you should be able to unscrew the bolts if needed.

Once the brackets are fixed to the wall, I'd just patch the plaster as best as one can. It is always going to have a <ahem> rustic look unless you replaster the whole wall. Much of it will be hidden by the radiator, so no one will know unless they go looking. A bit of reflective foil will also help to hide the plaster. It won't do much to combat heat loss through the wall though.

 

[frustin]

Ended up pumping the holes full of resin before inserting the rawbolts.

Thank you for your response. The plumber, that was tapping the rads (before a power flush), suggested these, but from what i understand, once they're in they're not coming out again. So with that in mind, i'd like to make the wall right since it's blown and you can see it flexing when pressing it. Those cracks have movement if i you push them as well.

I'd just patch the plaster as best as one can.

If i scrape it all out back to brick should i use this stuff: https://ebay.io/m/GIhoLk

 

[Kearn]

Thank you for your response. The plumber, that was tapping the rads (before a power flush), suggested these, but from what i understand, once they're in they're not coming out again. So with that in mind, i'd like to make the wall right since it's blown and you can see it flexing when pressing it. Those cracks have movement if i you push them as well.

If i scrape it all out back to brick should i use this stuff: https://ebay.io/m/GIhoLk

Definitely not - way too hard, this is good for bedding harder stone in walls etc or for limecrete floor slabs. Internally a nice soft putty mix, most of the usual suspects will do a bag or tub at the 22/25kg mark - problem is shipping is almost always by pallet, so it’s £70 regardless of what’s on it! so best to see if there is a proper supplier nearby to collect from, or equally someone who can supply putty then mix your own with aggregate.

 

[frustin]

Definitely not - way too hard, this is good for bedding harder stone in walls etc or for limecrete floor slabs. Internally a nice soft putty mix, most of the usual suspects will do a bag or tub at the 22/25kg mark - problem is shipping is almost always by pallet, so it’s £70 regardless of what’s on it! so best to see if there is a proper supplier nearby to collect from, or equally someone who can supply putty then mix your own with aggregate.

thank you for your response. So do you mean getting NHL 2 like this https://ebay.io/m/zUIHpA? please can you give me a link to a product so i know what i'm looking for? I'm new to lime.

Am i right in thinking it'd be good to scrape it all out and start again given what i've said about it being blown?

 

[Kearn]

Definitely not - way too hard, this is good for bedding harder stone in walls etc or for limecrete floor slabs. Internally a nice soft putty mix, most of the usual suspects will do a bag or tub at the 22/25kg mark - problem is shipping is almost always by pallet, so it’s £70 regardless of what’s on it! so best to see if there is a proper supplier nearby to collect from, or equally someone who can supply putty then mix your own with aggregate.

Seems you’re in a bit of a black hole regarding local suppliers!

I’d either bulk buy various things and store for the future to maximise the pallet cost. Or speak to a few of the suppliers, they can ship to local merchants instead of direct, so you’re paying a middle man, but may be cheaper than a pallet cost. Give a few of them a call, I rely quite heavily on Karl at Eden Hotlime for most of my materials, he will find a viable option if there is one.

 

[Kearn]

thank you for your response. So do you mean getting NHL 2 like this https://ebay.io/m/zUIHpA? please can you give me a link to a product so i know what i'm looking for? I'm new to lime.

Am i right in thinking it'd be good to scrape it all out and start again given what i've said about it being blown?

No, no NHL - it’s pretty hard and rigid, not ideal for soft bricks and will have a tendency to crack.

Really depends on the condition of what’s there - you’d be surprised by just how durable old lime is. If it’s all blown, then the key has gone - this can be rectified with stainless screws and stainless penny washers to pull it back in, And patch the gaps, may not be ideal in this scenario. Alternatively, you are back to the option of removing the minimum then patching the gap - it’s a tricky one to build the right thickness and a neat join as the line will shrink and pull in away from the joins and needs tending. You’ll want to cut the existing line with a blade, at 45deg so there is a key for the new lime to push under.

From your pic though, it looks like there is a skim of gypsum over any lime - colouration and the cracks are a giveaway. Try to prise this off first and see what you’re working with. Wallpaper scraper or stainless flexi cake icing tools are great from getting between the gypsum and lime - a steamer first helps break the gypsum bond and maybe some light taps to delaminate it.

 

[frustin]

stainless flexi cake icing tools

there's me looking at screwfix for a flexi cake icing tool...and you actually meant a cake that you eat - I tried these but there's no purchase.

 

[paulc]

These bolts should be ideal - https://www.ebay.co.uk/itm/403954049342 (use M6 by 50mm). Make sure the hole is around 60mm deep and reasonably clean. Pop a penny washer on the business end that would stick out of the wall. Pump some resin in, and then push the rawl bolt home. Quickly do the nut up so that the bolt starts to grip, and then stand back while the resin cures. Would be worth smearing a bit of vaseline, grease, or even a drop of cooking oil on the back of the washer first to stop any resin sticking to it.
Once you've got the bolts set in place, the radiator brackets can then be bolted to the wall - You may need to make the holes a little bigger (many of them are only 5mm or so in diameter). Then you can start picking out the loose plaster. Rather than using a NHL lime, you'd be far better off using a putty based plaster. Keep it in a sealed tub with a little bit of water on top, and it will never go off (got tubs here that are 5+ years old, and still good).
A couple of ebay links:

https://www.ebay.co.uk/itm/146525338865

https://www.ebay.co.uk/itm/235290706108

Might be worth having a chat with Mike Wye, Ty Mawr, or Anglia Lime to see if they could ship a ~5kg tub out any cheaper. Or if you were to head out to Norfolk (if you have children, there is lots for them to do), I could probably mix up something for you.