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trihouse
9th January 2012, 08:37 PM
Hi All,

Long time reader first time poster.

Just wanted to get some advice on a pergola with a roof I am trying to build. I have most of it figured out just this ledger part.

The pergola will be fixed to a wall and I will dynabolt the ledger to the wall however there is a window in between the span. Above the window is not brick but some weather board material. The window sits within the wall so it is not flush with the brick wall (there is a gap ~50mm) so I can not attach the ledger on the weather board material. The house is brick veener.

<---1200 WALL --><--- WINDOW 1800 ---> <---WALL 1200 --->

I have some left over wood (140 x 45) and thinking of this to use as the ledger, i can use 190 x 45 if required. Will this still be stable and work? I assume at each dynabolt point will act like a post more or less?

Thanks in advanced.

T

Grandad-5
10th January 2012, 10:38 AM
The size of the ledger is better determined by the size of the rafters being used.
I.E: You wouldn't use 140mm ledger to support 190mm rafters.
The span on the window is not an issue, so long as the ledger has enough fixings either side of the window.
The fixings themselves are important.
I used to have a chart showing how much weight various size Dynabolts will hold. I'm sure you could find one on the Ramset site somewhere.
But in the end, for ease of mind and to save time I usually opted for 1/2" x 4" Dynabolts into the heart of the brick at approx 450mm centres.
This was over engineering in all but the most extreme cases and meant I could buy that size in bulk to save $.

Always drill into the centre of the brick, not the mortor.

Occasionally, I would have issues with hollow core bricks. (The ones made by an extrusion method with holes through the middle.)
You'll be able to tell of you hit one of those holes.
Roughly measure where on the brick you had solid all the way through, and drill in the same place on the other bricks.

Having said all that, there has been a lot of progress in various fixing methods since I did this kind of work. Have a browse around the Ramset site and see what they currently have on offer. Then just follow their recommendations re size and number.

Grandad-5
10th January 2012, 10:51 AM
Sorry, just recalled something you may wish to use.
Purely for appearance sake, I used to countersink the ledger at each bolt. I bought a spade bit the correct size to match those little round domed plugs you can buy. A dallop of builders adhesive held them firmly in place. Made the world of difference once painted.

trihouse
10th January 2012, 11:16 AM
Thanks for the advice.

Unfortunately my brick is hollow and they have done it in such a way that I will always hit at least 2 hollow cavities. I have some spare bricks and 10mm dynabolt and will experiment with different types of anchors. Will post once I find the solution.

Thanks.

Grandad-5
10th January 2012, 11:47 AM
........they have done it in such a way that I will always hit at least 2 hollow cavities.

That sounds like the ones with more than one row of holes rather than 3 or 4 in a straight line.
You should still be right with a long enough Dynabolt.
Experiment with one of your spares.
If you can tighten up the bolt really hard and the brick doesn't crack then you're good to go.