Bloody Engineering Bricks, resin anchors and gaping holes

[c0wb0y]

Hey folks, I'm in a 1988 'new build' constructed entirely of engineering brick - and it's of the toughest type. Judging by several posts here (and replies like you need an SDS ) I'd say not many have encountered engineering brick. There's a 4" cavity behind the brick facade followed by light blocks.

My usual process with 7mm plugs is to get a 'punch' going with a pointed diamond bit before SDS'ing - the surface is way too smooth for non-hammer action starts. Even then, the hollow core of the brick mostly results in splitting. All my waste pipes, boiler flu etc. have had to be cemented around the edges despite using new diamond core bits.

So: I now find myself hanging a 10ft span of 4x2 and I'm thinking resin anchors (M12 or M14). This would serve as a top plate for a lean to with joist hangers etc.

The brick has the usual 3 holes and I fear an additional 12/14mm bore (plus all the vibration from the SDS) would result in total destruction, shattering and a complete breakdown of the brick.

1. Do I need to drill through both the outer and inner walls of the brick? Surely not as all the resin would just fall down the back?
2. If I drill just the front face with a 12mm core bit and catch one of the 3 brick holes, I'm still left with a huge opening requiring a lot of resin but more worryingly, the M12 threaded rod would only fit approx 40mm in: That doesn't sound like a lot to me!

Drilling into the mortar and other fixings like Rawbolts etc. have been ruled out. How do you guys do this? Please help (and apologies for the long post)

 

[footprints]

I used these sort things on my cavity wall https://www.ebay.co.uk/i/1818946521...MIqZCZ3fLY6QIVkrLVCh0oagTaEAQYAyABEgIPQPD_BwE

Screwfix sell them in smaller packs.

 

[c0wb0y]

Sleeved resin anchors: do these need to go through the brick or just the front face?

 

[23vc]

If it’s the top plate for a lean to, I wouldn’t worry too much as the load is pushing against the wall rather than away/straight down.
Just set them to a given depth, and it’s kinda out of your hands which bit of the brick it hits/which bit shatters.
I would say resin anchors are not required for this, and through bolt/sleeve anchors are fine. For mine I fixed it all with concrete screws then added a few through bolts afterwards.

 

[c0wb0y]

I wouldn’t worry too much as the load is pushing against the wall rather than away/straight down.

Hmmm - not sure I entirely agree with this. There's a shearing force due to rafters on joist hangers and the entire structure seems to want to pull 'away' from the main wall. I doubt anything will happen as its a few lengths of 3x2 and most of the structure is polycarbonate sheets! Sleeves are an excellent suggestion btw: I was aware of them but hadn't crossed my mind.

 

[23vc]

Not sure what your setup is, but if it’s a rafter on a top plate and bottom wall plate, and the bottom wall plate is strapped to the masonary, then any load on it is only going to push the top downwards and against the wall.
Yeah sleeve anchor type things, you don’t need resin.

 

[opps]

My usual process with 7mm plugs is to get a 'punch' going with a pointed diamond bit before SDS'ing

I find that the 4 point head SDS bits are less prone to slipping

 

[cdbe]

I did mine with good old fashioned brown Rawl plugs and wood screws. Just mark it all up so you're drilling into the solid part of the brick, not the holes. If you fix the plate at each end you can start off all the other holes by drilling through the wood as well, which will act as a guide for the drill bit when it hits the brick. I find the neatest way to get a 7mm hole in hard bricks is to start with a 5mm SDS and finish with a 7mm in a hammer drill. A 7mm SDS will smash a big sloppy hole and likely crack the brick.

 

[catlad]

Or 6 8 10 12 using an old piece of timber to drill your 6mm through to start, which you can hold to stop it wandering.