Author Topic: Heavy Duty Exterior Wall Fixings  (Read 610 times)

Heavy Duty Exterior Wall Fixings
« on: 22 May, 2021, 10:51:07 am »
I've bought a canopy for my side passage. It came with very substantial fixings that would have been great if my brickwork suited them. The problem is that my exterior bricks are very hard indeed for c.25mm in, then there's a void until the drill hits the other side. The supplied fixings were suited to solid bricks and are designed to expand where my bricks have the void, so are of no use.

The question is what fastening combination is suited to such brickwork? The canopy supports are plastic, although chunky, and the 'glasswork' is transparent, corrugated plastic sheeting. The total weight of the structure is not great, of course, but the load from winds whipping down the side passage will put much more strain on the fixings.

Any recommendations/guidance much appreciated.
Haggerty F, Haggerty R, Tomkins, Noble, Carrick, Robson, Crapper, Dewhurst, Macintyre, Treadmore, Davitt.

Re: Heavy Duty Exterior Wall Fixings
« Reply #1 on: 22 May, 2021, 11:10:07 am »
Most bricks have a depression in them, it's called a  frog. Sometimes bricklayers lay them upside down thus leaving a hollow. Often, when drilling into brickwork this hollow is come across.  Usually conventional screw and rawlplug fixings fail.
The most successful way to fix into this brickwork is to use a two part resin and threaded rod.
Following the drilling the brick dust must be removed , puffers are designed for this.  The two part resin is pumped in using a mastic gun. The nozzle contains a series of plastic fins that automatically mix the resin. I always expel the first 10 cm bead on waste paper to ensure properly mixed resin fills the hole. The threaded rod should be 4mm smaller in diameter than the drill bit to ensure adequate amount of resin grips both hole and threaded rod. Hope this helps

Re: Heavy Duty Exterior Wall Fixings
« Reply #2 on: 22 May, 2021, 03:42:04 pm »
Thanks. That's really useful advice and I'd no idea that solution existed.
Haggerty F, Haggerty R, Tomkins, Noble, Carrick, Robson, Crapper, Dewhurst, Macintyre, Treadmore, Davitt.

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Re: Heavy Duty Exterior Wall Fixings
« Reply #3 on: 22 May, 2021, 03:54:44 pm »
I'm sure I replied to this earlier  - senior moment.

I think the bricks being described are the hollow ones (made to be cheaper, lighter and use less material but the same effect) - like this :  - so not the frog but drilling into the void.

My suggestion for fixing would be long Rawlbolts - like this :  https://www.screwfix.com/p/rawlplug-rawlbolts-m10-x-140mm-5-pack/88686   - they should bite into both sides of the hollow bricks.   It might be a better solution to fix a timber batten to the wall and then fix the canopy to that - difficult to comment without sight of the job.

The rod and resin solution works BUT you have to be right first time with the drilling and if anything needs to be changed later you can't get them out - the only solution is to grind them off flush with the wall!  The Rawlbolts can be removed/replaced (just the threaded sleeve in the wall)

Whatever you do you'll need a beefy SDS drill for the holes.

Re: Heavy Duty Exterior Wall Fixings
« Reply #4 on: 22 May, 2021, 10:31:45 pm »
Most bricks have a depression in them, it's called a  frog. Sometimes bricklayers lay them upside down thus leaving a hollow. Often, when drilling into brickwork this hollow is come across.  Usually conventional screw and rawlplug fixings fail.
The most successful way to fix into this brickwork is to use a two part resin and threaded rod.
Following the drilling the brick dust must be removed , puffers are designed for this.  The two part resin is pumped in using a mastic gun. The nozzle contains a series of plastic fins that automatically mix the resin. I always expel the first 10 cm bead on waste paper to ensure properly mixed resin fills the hole. The threaded rod should be 4mm smaller in diameter than the drill bit to ensure adequate amount of resin grips both hole and threaded rod. Hope this helps

 I installed a 12m long metal framed canopy with sheet metal covering along the front of the house using the above method. Its still solidly fixed.

Re: Heavy Duty Exterior Wall Fixings
« Reply #5 on: 23 May, 2021, 05:58:14 pm »
Thanks all. I've managed to borrow an SDS drill, as my mains and cordless ones both struggled.

The timber batten idea is a good one, but I'm already fairly close to the neighbour's adjoining fence and don't want to get any closer.

If I do go down the resin route, I assume that some time is needed for the resin to cure before applying load. If so, how long?
Haggerty F, Haggerty R, Tomkins, Noble, Carrick, Robson, Crapper, Dewhurst, Macintyre, Treadmore, Davitt.

Re: Heavy Duty Exterior Wall Fixings
« Reply #6 on: 23 May, 2021, 06:12:30 pm »
Two part resin cures within an hour. If the work is carried out according to instructions, then you will be able to apply load to the fixings certainly within two hours.

Re: Heavy Duty Exterior Wall Fixings
« Reply #7 on: 24 May, 2021, 10:51:46 am »
Be careful with the drilling. That type of brick is prone to fracturing if you go at it too hard with a big hammer drill.

Ditto with tightening up the rawlbolts. Too hard and you break the brick.
<i>Marmite slave</i>

Re: Heavy Duty Exterior Wall Fixings
« Reply #8 on: 24 May, 2021, 11:40:03 am »
Two part resin cures within an hour. If the work is carried out according to instructions, then you will be able to apply load to the fixings certainly within two hours.

Resin fixings are ace. Our mantel piece is a 4inch square oak beam. Its held in place with two threaded steel rods resin bonded in. The chimney would collapse before you got that thing off the wall.
I think you'll find it's a bit more complicated than that.

Re: Heavy Duty Exterior Wall Fixings
« Reply #9 on: 26 May, 2021, 04:31:39 pm »
I've bought the resin and rods from Screwfix. What really sold me on the solution is that they now do centering inserts to help locate the rods and remove the need to clean the hole - although I shall of course blow away any excess dust.
Haggerty F, Haggerty R, Tomkins, Noble, Carrick, Robson, Crapper, Dewhurst, Macintyre, Treadmore, Davitt.

Re: Heavy Duty Exterior Wall Fixings
« Reply #10 on: 01 June, 2021, 11:28:45 pm »
Be careful with the drilling. That type of brick is prone to fracturing if you go at it too hard with a big hammer drill.

Bosch Multi-Construction drill bits were always my go-to if I had any qualms about bringing out the SDS. Very effective on anything short of concrete, and *much* more refined.