Knock through

Hey all,

I am just planning my knock through.
I have a nearly 7 meter wall to come out at the back of my house. There will be 4 beams - two large ones @ 5.3 meters long. One of which will support the inside leaf and one the outside leaf. The inside one sits under the 1st floor joists which run perpendicular. The outside one is slightly taller but both will be bolted together. The other two smaller beams which are 1.6 meters long will be plated onto the larger beams to extend over a smaller gap.

So I plan to use 12 props and some 3x3 timber as needles. The inside props will support the first floor joists which are built into the wall anyway. I will spread the load as much as I can under and above each prop and screw the 3x3s onto props and joists. I would then hope to use some block and tackle (attached to some beefed up needles) to help raise the beams most of the way to the pads.

So questions I have -

1. Does this sound OK? Any suggestions?
2. Is it best to add morter to top of beam and push this up into the brickwork to the add slate under ends of beams? Or just sit in beams and push morter into gaps/joints?
3. Should I take all of the wall down before adding beam or just take wall down where beam will go and knock rest down when beam is in place.

Thanks in advance for your help

How are the inside props supporting needles and floor joists?
If you're expecting the joists to support the inner skin at any time be aware that there may be gaps between the tops of the joists and the brickwork.
Be careful if the inner ground floor is timber and you're propping off it - I took some floorboards up and propped off the oversite.
You might want to tie the props together with scaffold - I think you're supposed to for wide openings.
I think the mortar and up, or packing afterwards etc depends on what you end up with on the job - in my case the steels didn't sit with space for a full brick on top and quite a few came loose with cutting out the slot for the steels so even though I may have intended to jack up with a bed on top I ended up rebuilding above afterwards including a course of cut bricks. It also helps to have a bit of wiggle room when getting the steels in.

Before doing this stuff I always thought it odd to put the padstones in after the steels, but in practice it helps with manoeuvring space and stops you knocking them off their beds with the steels.

If it's not in the way I'd focus on getting the steels in and props out as quick as possible and forget about the wall till later.

You can also do a lot of preparatory work such as creating most of the slot before propping - just leave every 4th brick in.

Probably too late now but did you consider putting the steels higher to avoid a downstand? Makes it look like one big room rather that two rooms knocked through.

I'd have a few extra acrow's on hand for "emergencies".