UKC

Hi guys, 

After a bit of advice, feel free to tell me its a shit idea.

I want to put a bolt in on the side of my house to practise SRT, near the top but far enough down to not have the wall "fold" on me, just above the floor of the loft probably, its about 8 feet below the apex. It's breeze block inner with red brick cladding. 

Is this in any way safe? I'm loathe to put in an any "ordinary" bolts used for climbing as I don't trust the brick not to have cavities etc. If I put a long bolt through and braced it on the inside would that be safe? Perhaps I could use resin as a belt and bracers measure to stop the bolt working its way loose/unscrewing, I'd use nyloc anyway but just to be safe. 

Any advice appreciated, thanks 

I have just cut a red engineering brick out of a 40 year old wall, This is the type with 3 holes in it.

Even cutting out the mortar on all 4 side's with a proper cutter I still had to break the brick to get it out.  Drill it and fit an expanding rawplug you will be fine .

Thankyou for that, mate. Very reassuring  

My only worry is its only 11 years old and was built by the lowest bidder.

Even if you drill 900mm below the apex/ridge there will be around half a ton of brickwork above the bolt. That's just the outer leaf and not counting the weight of the roof.

Any chimney flues to consider?

Personally I would ( and have) used  10mm thunder bolts and a standard M10 hanger ( the bolt just fits). The brick will be 102.5 mm thick , so ideally a bolt just longer would be ideal, so as to not bridge and compromise the cavity.

It is difficult to source stainless thunder bolts but a galvanised one should last a few years unless you live on the sea front.

10mm stainless steel studding bar could be used through both leaves and insulation but best drilled at a slight uphill angle to drip towards the outside. Do not tighten too much or the leaves of brick /block will be drawn together, locking nuts both ends.

Both these (dry) options have the advantage of being easily removable 

Alternatively glue in M10 SS engineering bolts . These should screw out with an extended socket.

Steve McClure bolted the side of his house in lockdown 1 (admittedly not red brick).  What’s good for the goose...

Neither the inner or outer leaf on the gable should be bearing any of the load of the roof other than in some circumstances a few tiles/slates

If the chimney is internal there isn't much of a problem unless the bolts used are ridiculously long

Exactly this, but it does depend on the type of brick used (and the type of frog in the brick)

Ask for a rawlbolt rather than a rawlplug, asking for a rawlplug will see you leaving the shop confused as to why the guy behind the counter has given you a little piece of plastic

If you're unsure then get a professional in to do the job, do not under any circumstances attempt it yourself.

Correct, if the roof is of trussed rafter construction and there are no purlins bearing on the gable wall. Good point. The gable wall should have a number of restraining straps tieing it into the roof, which would be worth checking for if accessible. 

it's odds on that your external brick will be "vertically perforated" (3 hole).

rawlbolt, thunderbolt, (expansion wedge) throughbolt, resin - would all work.

I'm not sure about thunderbolts in brick, although I'v not used them in brick myself.  they are sensitive to hole-size and you can damage the thread screwing them in. the benefit is you can remove them easily leaving only a hole.

rawlbolt or through: I'd go for rawlbolt type for a larger (longer) expansion sleeve.

if you're going high enough to hurt yourself - use at least 2 (if not 3) staggered vert and horiz 

The short answer is, no-one will have an answer for you. All bricks are different and all bricks are designed for vertical compressive strength whereas you are wanting to point load a single brick at a perpendicular angle. With a static load it would probably be ok but I don't think many people would be willing to guarantee a single bricks integrity. As regards your roof, if it is a truss design then there will be negligible loading, but if it's a purlin and rafter design then all of the roofs load will be on your internal leaf (in both cases there is no load on the external leaf). If your mortar is old or weak you might also cause buckling to the brickwork, this will be expensive to fix. If you bolt through both walls and add a spreader plate on the internal leaf it will no doubt be stronger, but any failure may effect the buildings structural integrity if it's a purlin and rafter roof. Bolting through may also compromise your cavity and provide a bridge for damp and cold to penetrate. Depends what your willing to risk.

As regards bolt type, again it depends on the bricks, some won't want to bite on certain bricks and if you use resin you may end up just filling frogs/perforations or pouring it down your cavity. You can use thunderbolts in brick but they don't like perforated bricks, I've had them specified by engineers on new floors (although they usually like you to tie in every third joist).

If you have a chimney on the gable end be careful not to drill through it. However, if you do have a chimney there why not just sling it and use that as your anchor. 

It’s possible to hire a hydraulic pull tester if you want to be sure your anchors are solid - they’re pretty simple to use.

Personally I’d go with the Rawlbolt option as the most reliable. I wouldn’t recommend resin/threaded bar unless you’ve done it before.

Ok maybe not . . Settle for rings in a tree then  . . . But no ! with trees there is always . . . 

SRT? You’re just going to be abseiling? I can’t see you pulling the wall over on yourself or ripping a bolt out if you use the right bolt.
 

Most of the load will be downwards. I think there are specifications as to how many courses of bricks, or mm, you need over the top of joist hangers. You can look that up. 
 

I have bolted a timber wall plate to the side of my garage to hold a lean to roof. Maybe distribute the load in that way. 
 

Only concern is ingress of damp. So maybe think about at least some sealant around the bolt. 

Who knows but whatever you do, don’t just use a single bolt... that’s just a big no-no in any situation unless you have no choice. 

Here's a picture of neighbour's side of common chimney on our semidetached. Our roofer rebuilt our chimey. Neighbour's roofer rerendered but didn't rebuild. Structure looks fine from ground.