Winching up replacement window frame from concrete lintel?

[alchemy]

Hi All,
I need to replace the upstairs back windows in my 1930's semi. The new window will be made of oak, so quite a bit heavier than pine or uPVC. I have a little DIY scaffold tower to work from on the outside and will have someone inside to help me. The opening on the inside of the house is slightly smaller than the 'brick to brick' opening on the outside, so there would be a bit of 'jiggling' the heavy frame around to get it outside and into position. I'm concerned about damaging the frame or, worse, falling off the scaffold tower during that part!

The top of the opening is formed by the concrete lintel that supports the roof. I was wondering if I could instead hoist the window frame up from outside the house using this lintel, as per the diagram below?

The window frame, without windows and glazing, will weigh about 30 to 40Kg. I have a hand winch with steel cable and fabric slings rated to 1.6 tonnes... that would go in the attic and I attach it to the base of the roof struts. The winch cable then passes over the concrete lintel and attaches to the window frame outside. One person operates the winch and the other helps guide the frame up into position.
Therefore some of the 30Kg force acts down on the lintel and some is acting sideways on it while the frame is winched up. These forces are applied at one single point in the middle of the lintel.
It feels to me that I am probably worrying over nothing but is anyone able to reassure me that I am not likely to crack the lintel or pull the roof struts out of place if I attempt this?

Thanks very much!

 

[bernardgreen]

My concern would be the horizontal force exerted on the lintel by the steel cable. Lintels and the way they are fitted in the wall are not designed to resist horizontal forces. The steel cable could pull the lintel out of the wall.

 

[23vc]

Evening Heath Robinson,
I would sort out your scaffolding so (1) it’s rock solid and safe and (2) there’s a lower platform/intermediate platforms for you and your mate to safely lift the window up to the right height.
Or just carry it upstairs inside.
But to answer your question, no you won’t damage any lintels/roof structure. Does the room not have a ceiling?
Edit: just looked at the pic again. Have you not got a soffit?

 

[cdbe]

Please post the video. It reminds me of the time me and my mate Ollie tried to get that piano up the stairs.

 

[catlad]

Surly you can just sling it on your shoulder and carry it up the ladder!

 

[plastic_peanut]

At 30-40kg this should be manageable and no need for a winch.
As mentioned take it up stairs internally and pass through the window. It shouldn’t be as challenging as you are envisaging

 

[alchemy]

Thanks for the replies everyone. Yes I reckon I am over thinking it ... 'Heath Robinson' as you say!
We'll just pass it through from the inside I think.
Thanks again!