Sh1tty horrible "wimpey no fines" walls!

Steveanem · Mar 31, 2016 9:39:21 pm

Took delivery of our vertical designer radiators today.

I knew I might have problems drilling into these walls but didn't realise it would be quite so bad!

I marked up and drilled for the brackets and, as expected the drill bit took a detour into the gaps between the aggregate and made a right mess of the wall.

For those of you unfamiliar with Wimpey no fines concrete, it was a method of building houses quickly with a concrete mix of just cement and course aggregate (no sand hence "no fines"). The concrete was cast in situ using reusable formwork and pretty much resembles a giant rice crispies cake slab in grey!

So after completely messing up fixing holes for the first 2 brackets, (2per bracket required x4 brackets) realising the holes were not going to be aligned, and that the aggregate was being dislodged by the drill, I decided I would not drill any further holes until I find a solution.

I have read that there are some 2 part resins available for fixing anchor points where masonry is liable to crumble and I'm wondering if I could use this stuff to fill the holes and then redrill them, but I'm not sure if it will just pull out of the wall in a big lump!
Nightmare.

This is what I'm left with...you can see the aggregate in the holes, after I've removed the dislodged pieces....

fr499y · Mar 31, 2016 9:55:26 pm

The horror stories I have heard about wimpey homes and others build with the same method is a joke. I've known people in 2 year old houses ( ok so not the same as the 50's WNF constructions ) with walls that pretty much crumbled and cracked. IIRC, Wasn't there a time when home insurance on these no fines houses was nigh-on impossible to get? Can't beat the build quality of early 1930's etc houses. a hour and 4 drill bits later and you might have managed to put up a shelf.

Back to topic, No idea about the resin.

Marty · Mar 31, 2016 10:21:04 pm

Something like this will do the job mate :)

http://m.screwfix.com/details.htm?id=14364&csnbl=1

But set the anchors in it to go off don't drill it after

Steveanem · Mar 31, 2016 10:31:51 pm

Quote from: fr499y on Mar 31, 2016 9:55:26 pm

The horror stories I have heard about wimpey homes and others build with the same method is a joke. I've known people in 2 year old houses ( ok so not the same as the 50's WNF constructions ) with walls that pretty much crumbled and cracked. IIRC, Wasn't there a time when home insurance on these no fines houses was nigh-on impossible to get? Can't beat the build quality of early 1930's etc houses. a hour and 4 drill bits later and you might have managed to put up a shelf.

Back to topic, No idea about the resin.

I did have my reservations when buying the house but the surveyor told me that despite everything they are pretty solid houses and will probably last another 60 years plus. They were only ever meant to be a temporary "emergency house" post WW2. There are other types of concrete builds such as prefab panels and a type with internal metal banding that is renowned for blowing and cracking due to moisture ingress, but apparently these are not considered a risk in the same manner.

Steveanem · Mar 31, 2016 10:32:57 pm

Quote from: Marty on Mar 31, 2016 10:21:04 pm

Something like this will do the job mate :)

http://m.screwfix.com/details.htm?id=14364&csnbl=1

But set the anchors in it to go off don't drill it after

Nice one thanks just been looking at a similar one By Rawl but this one looks better. Cheers.

Steveanem · Mar 31, 2016 10:35:42 pm

@Marty have you had experience of the stuff? Will it try and run out of the hole or is it fairly stiff in consistency?

Mike · Mar 31, 2016 11:49:00 pm

I never even knew this existed.

I've seen big holes filled with hardcore

but in the ground not house walls!?

Doesn't it all settle over time leaving big hollow gaps at the top of the upstairs walls?

Marty · Apr 1, 2016 12:19:18 am

Quote from: Steveanem on Mar 31, 2016 10:35:42 pm

@Marty have you had experience of the stuff? Will it try and run out of the hole or is it fairly stiff in consistency?

Father inlaw has used it to anchor things in the past with no issues :)

Masking tape over the top will hold it in but when I see father inlaw using it the stuff was quite thick

Steveanem · Apr 1, 2016 12:42:34 pm

Quote from: Mike on Mar 31, 2016 11:49:00 pm

Doesn't it all settle over time leaving big hollow gaps at the top of the upstairs walls?

How do you mean @Mike? I just want to use it to provide a fixing for the radiators. Are you referring to some other use for it?

Apparently it's sets rock solid and opinion seems to be that the wall would crumble around it before the stuff itself would fail.

Steveanem · Apr 7, 2016 9:14:11 pm

Well I wasn't going to let some poxy rice crispies concrete wall beat me!

I fashioned some spacers using din rail (as used in electrical distribution panels etc) to keep the correct distances and some 8mm threaded bar for the anchors. I got the chemical mortar/resin from Screwfix as per @Marty thanks for the link mate!
It's obviously not finished but it's looks something like this....

Marty · Apr 7, 2016 9:27:27 pm

Nice one glad it sorted the issue always good to win haha

Sh1tty horrible "wimpey no fines" walls!

Sh1tty horrible "wimpey no fines" walls!

Sh1tty horrible "wimpey no fines" walls!

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