Lifting a lintel with a Genie Lift - no room for legs?

[mikkymo]

I'm taking out the back of my attached garage to add a rear door. There's a 10' high block wall supporting the roof and a brick outer wall which isn't supporting anything.

My plan was to have the lintel sitting at the base of the wall, support the roof joists above with acrow props, then hire a Genie lift to lift my 9' lintel up (between acrows and wall) and slot it into place.

However, I've just noticed that the legs of the Genie lift will be poking further out than the forks (obviously so it doesn't topple over).

Option 1: Take both walls down with just the acrows in place, then lift the lintel, or;
Option 2: Knock a few blocks/bricks out at the base of the walls for the legs to slide through, and take the walls down after?

What do you guys reckon?

 

[noseall]

How heavy is the lintel?

We had to hire a crane for our last pair but this was because they were 340kg's each. The two smaller ones in the building were 82 kg's each and were a doddle for three blokes.

 

[mikkymo]

Worked it out that it will weigh 145kg... The lintel will be going in at 10' high, so even standing on trestles it would be a stretch...

 

[noseall]

Worked it out that it will weigh 145kg... The lintel will be going in at 10' high, so even standing on trestles it would be a stretch...

What are the dimensions of this lintel?
What is the opening width?

 

[mikkymo]

Dimensions are 2700 x 215 x 100mm - prestressed.
Opening width is 2280mm (for 7' door).

 

[noseall]

Wouldn't you be better off with a more modest section steel beam rather than the behemoth of a concrete lintel?

 

[mikkymo]

I completely agree, but my helpful BCO pointed out that the front door has a 2440mm x 175 x 100mm lintel over it and if I copy the structure at the front, I don't need SE calcs. It's supporting all the same loads.

He also suggested 175mm is too small for the opening - 215mm would be a better choice. Plus I may as well install a prestressed lintel as it's only a few quid dearer and the whole heap will be well spec'd for the load above it. The lintel that's up there has 80-100mm bearing either end, so I was thinking a longer lintel with 150mm++ bearing would be better.

If I were to support the joists with acrows and cut out 2 holes in the bottom of the wall with an angle grinder for the legs to fit through (300x300mm) whats the worst that could happen? Lose a few bricks above my openings in the bottom? Inner and outer walls collapse?

 

[Norcon]

Slide a pallet unto the forks and have it over reaching the legs.
Then lift the lintel unto that.
You could stack a few bags of cement to act as a counter balance to keep it from tipping if need be.

 

[noseall]

I completely agree, but my helpful BCO pointed out that the front door has a 2440mm x 175 x 100mm lintel over it and if I copy the structure at the front, I don't need SE calcs. It's supporting all the same loads.

But what about the faff factor, the cost of the genie lift and actually getting the thing into place before even lifting?

Surely this alone outweighs wrestling with such a bonkers size beam?

 

[mikkymo]

Got a rough cost this morning to visit and do calcs for a steel beam from 2 local SEs - cheapest was £120.

The lintel is straight from the concrete supplier, so it's £30 all in. Genie will cost me £50 for a full days use so going the steel route just isn't worth the hassle and extra cost.

Seems like the easiest option is to stick the acrows in, cut and take down both walls, then lift the lintel into place with plenty of room to manoeuvre. Just means working for longer with only acrows supporting the roof, but sure isn't that what they're made for?