Fixing heavy radiator over insulation...

delmonta

FreeBear said:

delmonta said: Ah ok you are both saying different things. But surely the elongated holes don't let you adjust anything unless you don't fix the other hole. Or maybe you are meant to do the second hole after to secure it in place. 

Drill the bottom holes first for the elongated holes. Offer up the brackets, get them level and square, then nip up the screw/bolt. Once firmly fixed, use the top round hole as a guide to drill the remaining fixing holes. Remove the bracket, insert the resin & fixings. Reattach the bracket and nip up the fixings lightly, and after checking all is level and square, leave for 24 hours for the resin to harden fully.

After tightening the fixings the next day, the radiator can be rehung and plumbed in.

Thanks very much, what do you mean by nip up?

What do you think about using the elongated holes for the resin fixings, then getting them all in and level, then using masonry screws for the other holes? This would make it much easier to get everything lined up perfectly and level

Jeepers_Creepers

I think your plan is good, delmonta.

I fitted a couple of column rads recently, and both bracket holes were elongated, so the bracket could be tweaked even with both bolts in position.

I suspect the idea is with yours - as you've concluded - is that you use the elongated ones to fine-tune the levels, and then drill through the fixed holes for the extra-secure fixing.

In which case I think your idea is sound - get the brackets dead level and vertical using a good spirit level. Draw around each bracket so you can reposition them perfectly. Drill through the centre of the elongated holes for the resin fixings - yes, you'll need a nice long SDS drill bit!

Once set, you can bolt up the brackets and do a test-fit of the rad. For this, don't tighten the nuts up tight, but nip them up to grab the brackets and hold them quite firm but still moveable with a thump. If the test-mounted rad isn't level, prop something up between the floor and the low corner to get it level (or a fraction more), and then use something like a long screwdriver and a small hammer to 'tap' up the 'wrong' brackets until they make contact with the rad again. Once all 4 brackets are making good contact with the level rad, gently remove the prop, and check that the rad now remains level.

Remove the rad and mark the brackets in their new correct position, just in case you knock and move them. Tighten the nuts a bit more to properly hold the brackets in place.

Now drill through the 'fixed' holes, suck/blow out the dust, and hammer in something like a frame-fixing if you can get one the right length. You have various options here; ordinary plugs and screws - if you can get the plugs into position ok - or the type of frame-fixing that has a plug already on it, or even a 'masonry screw' like https://www.screwfix.com/p/easydrive-countersunk-concrete-screws-7-5-x-150mm-100-pack/7465h (You want a smaller pack tho'!) Or,

https://www.screwfix.com/p/rawlplug-kkr-pa6-nylon-frame-fixings-10-x-160mm-12-pack/8590g

delmonta

Jeepers_Creepers said:

I think your plan is good, delmonta.

I fitted a couple of column rads recently, and both bracket holes were elongated, so the bracket could be tweaked even with both bolts in position.

I suspect the idea is with yours - as you've concluded - is that you use the elongated ones to fine-tune the levels, and then drill through the fixed holes for the extra-secure fixing.

In which case I think your idea is sound - get the brackets dead level and vertical using a good spirit level. Draw around each bracket so you can reposition them perfectly. Drill through the centre of the elongated holes for the resin fixings - yes, you'll need a nice long SDS drill bit!

Once set, you can bolt up the brackets and do a test-fit of the rad. For this, don't tighten the nuts up tight, but nip them up to grab the brackets and hold them quite firm but still moveable with a thump. If the test-mounted rad isn't level, prop something up between the floor and the low corner to get it level (or a fraction more), and then use something like a long screwdriver and a small hammer to 'tap' up the 'wrong' brackets until they make contact with the rad again. Once all 4 brackets are making good contact with the level rad, gently remove the prop, and check that the rad now remains level.

Remove the rad and mark the brackets in their new correct position, just in case you knock and move them. Tighten the nuts a bit more to properly hold the brackets in place.

Now drill through the 'fixed' holes, suck/blow out the dust, and hammer in something like a frame-fixing if you can get one the right length. You have various options here; ordinary plugs and screws - if you can get the plugs into position ok - or the type of frame-fixing that has a plug already on it, or even a 'masonry screw' like https://www.screwfix.com/p/easydrive-countersunk-concrete-screws-7-5-x-150mm-100-pack/7465h (You want a smaller pack tho'!) Or,

https://www.screwfix.com/p/rawlplug-kkr-pa6-nylon-frame-fixings-10-x-160mm-12-pack/8590g

Wow thanks for the step by step, very useful for a noob like me! That sounds like a plan

I think I'll go with concrete screws at the end, seems the easiest as getting plugs in through 100mm of insulation sounds awkward. 

One thing, I don't have anything to clean out the holes for the resin, I couldn't get a can of compressed air, or a little tubular wire  brush thing. I was hoping that just blowing very hard through a straw might be enough, and maybe getting my vacuum on it. What do you think? I dont want to compromise the bond

Jeepers_Creepers

Sellotape the straw to your vacuum nozzle to seal off air leaks, and insert slowly.

What is the material behind the insulation - is it decent brick or block? If so, you might prefer to go for the masonry screw/thunderbolt type fixing for all 8 holes. The main drawback with resining-in threaded bolts is the aesthetics of the nut and exposed thread, and also having to get the sticky-out amount just right so's you don't feel you need to grind off the excess afterwards.

I wonder if these will do? https://www.toolstation.com/masonry-torx-frame-fixing-screw/p39995 (you'll need 'cup' washers for the heads).

delmonta

Jeepers_Creepers said:

Sellotape the straw to your vacuum nozzle to seal off air leaks, and insert slowly.

What is the material behind the insulation - is it decent brick or block? If so, you might prefer to go for the masonry screw/thunderbolt type fixing for all 8 holes. The main drawback with resining-in threaded bolts is the aesthetics of the nut and exposed thread, and also having to get the sticky-out amount just right so's you don't feel you need to grind off the excess afterwards.

I wonder if these will do? https://www.toolstation.com/masonry-torx-frame-fixing-screw/p39995 (you'll need 'cup' washers for the heads).

Good idea, why didn't I think of that with the straw! 

It would be easier to use masonry screws. But this radiator is really heavy, and if it came off the wall it would be a nightmare, and cause a leak that could ruin my floor! I'm often away for days. 

So if resin is stronger I'd like to go with that. The nuts and threaded rod will be behind the radiator. I doubt you'll see them. I could paint them black as the radiator is black 

fenwick458

I've just recently been on a job where the plumber had the same problem. they were getting a good fix behind using long fixings but the problem was before the brackets got tight, the plasterboard and insulation caves in
there was some talk about maybe using some corefix fixings , but in the end they just cut sections out with a multitool, bolted peices of 4x2 to the wall and then plastered over them.
seemed a bit overkill to me at the time but I later found out some were 150kg so maybe justified

delmonta

fenwick458 said:

I've just recently been on a job where the plumber had the same problem. they were getting a good fix behind using long fixings but the problem was before the brackets got tight, the plasterboard and insulation caves in
there was some talk about maybe using some corefix fixings , but in the end they just cut sections out with a multitool, bolted peices of 4x2 to the wall and then plastered over them.
seemed a bit overkill to me at the time but I later found out some were 150kg so maybe justified

Ok that's a little worrying. I wonder if that will happen here too. The brackets are only about 5cm x 4cm. Not much spread on the pressure. 
The plumbers just turning up now, but honestly not sure if I trust these guys to care as much as I do. They want to use Flexi pipes instead of copper and said that's normal. I'm sure it's not

Jeepers_Creepers

delmonta said:

So if resin is stronger I'd like to go with that. The nuts and threaded rod will be behind the radiator. I doubt you'll see them. I could paint them black as the radiator is black 

No prob - man who go to bed with rad problem wake up with solution in hand. (That's plumber-!!!!!!)

Yes, your reason for going 'resin' is a good one. And it also solves the 'crushing' issue

Before resining-in the threaded bar, do one more wee thing - enlarge the hole in the p'board layer by the diameter of the nuts you will use, and to the depth of the nut thickness. Doesn't matter is it's slightly untidy...

Resin in threaded bar as before, and allow to set. Now fit a first nut and spin it right down until it's a washer-thickness below the p'board surface level. Put on a washer. Fit your bracket, add another washer and then the second nut. Do up that second nut and the bracket will be securely held at the correct position between two nuts and two washers, with the lower washer now sunk into the p'board surface but with no risk of 'crushing' it any further. (Have a play first - you may wish to fit the first nut and washer to end up slightly - 1mm-ish - below the surface level so the bracket is tightly drawn in to the p'board.)

Then use the masonry screw for the second fixing.

Jobbie jobbed.

Mutton_Geoff

What "batten" is fitted for the rad to be hung? If it's 4x2 then I'd quite happily hang the radiator on that if the timber has been fixed properly. The problem with longer fixings through to the brick means you are introducing a length of steel rod from the solid fixing to the rad. This then allows a lever force to be applied instead of just a sheer force that would normally apply if the rad was fixed straight to a timber frame. All of the weight is acting downwards and even small fixings have a huge amount of sheer capability (eg the kitchen wall unit example above).

If the builder was aware you were going to hang a rad, ask them how the timbers are fixed and bear in mind, almost all the weight will be acting straight down to the floor, not trying to pull the rad away from the wall.

I'd use the long studs if I was hanging a wall mounted basin in a bathroom where there is a lot of lever force, but not for a wall hung rad.

Jeepers_Creepers

delmonta said:

Ok that's a little worrying. I wonder if that will happen here too. The brackets are only about 5cm x 4cm. Not much spread on the pressure. 
The plumbers just turning up now, but honestly not sure if I trust these guys to care as much as I do. They want to use Flexi pipes instead of copper and said that's normal. I'm sure it's not

I think it's reasonable to consider that flexis will not last as long as copper or plastic. This is 'cos they have 'rubber' (neoprene?) hoses inside them, and there are many instances of these perishing or even creasing/folding/collapsing over time. I would want assurances that the items used have water-tight guarantees for decades...

If they want a little movement - and that would be perfectly understandable especially if the pipes are coming out the back of the wall? - then why not use copper-flexi 'concertinaed' pipes, or even plastic pipe?

I had this issue with mine - the pipes were coming out from the wall behind the rads, so had to be in exactly the right position to mate up with the valves, and with only a short 2" amount of pipe showing. Lawdie - that's too much precision. So I made room behind the boards (this was a new extension, so could do this before the p'boards were D&D'd in place) and ran the pipes in 10mm plastic microbore, changing to 15mm copper tails at the last point behind the boards. That gave me the required 1/2" plus 'play' room, and I needed every bit of it... Plastic decorative collars covered the mess