Raise Garage Roof by 9 inches

[SFK]

Dear All,

My issue is that my Garage Ceiling is too low at just over 6feet (I keep hitting my head on the lights).
Hence I wish to Raise the roof by say 9 to 12 inches.
I know that I could take off the roof, add a brick layer and then put roof back on. But it is a big roof and expensive to do that for a small return.

BUT out interest and having seen the USA series "House Movers" (in which I guess they would use two RSJ's running along the length of the Ceiling Joists and then 4 hydrolic rams & blocks to lift it), is there any method in the UK that could temporary lift all of the roof in one go so that a new brick course could be added to the top of the existing wall and then roof dropped back down? .

Details:
1) I have a Garage that is 4.5m wide by 7meters long.
2) Walls are Concrete Breeze Block (single thickness).
3) Roof is pitched, with Ceiling Joists lying on wood Wall Plates.
4) The Gable walls are wood Clad (not brick).
5) The roof is tiled with Thin Fake slate tiles (Asbestos Tiles).

With thanks, SFK

 

[lostinfens]

Actually did raise a garage roof in Guildford last year to accommodate a new door. It was a flat roof, which probably made it easier, but if your ceiling joists are tied in sufficiently or can be packed against the roof spars, then there is little reason why you can not do this to your roof.

You,d need some fairly solid timbers, 4x2s would probably do it and several acrow props, at least 4 each side. I'd pack between the ceiling joist and spar with lengths of timber then fix 4x2s ( or bigger) to the underside of ceiling joists close to but not tight to each wall. Then after ensuring that there is no physical fixing of wall plate to wall, space acrows down length of wall, leave a gap from corner perhaps of 1 joist, then space at least 4 down length of wall . Now drink beer. Then slowly raise props on 1 side enough to get a packing of about 2-3 inches, and drop back onto packing, then do same other side. It is important that you do not raise both sides at the same time or the whole roof could just sway in the breeze.
If your going for 1 course of blocks higher, then I would put a half course on each side, rather then attempting a whole course in one go. You would find this a simpler task than trying to feed in a full block ( you can easily cut them lengthways with a disc cutter). I would lift both sides slowly, pack one side with a split block, raise the other side about 2" higher then bed in the split blocks. Leave this to go off for a while then repeat the process.
Dependent on the weight, and how brave you feel, you may be wise to give the first courses a night to go off, work it out on the day.
Using this method, you could raise your roof to your requirements.
Be warned ! Check everything as you start and keep checking. Make sure that your roof covering can stand the strain and that your walls are structurally sound and can be built on. Check the fixing of the fascia, if necessary remove the gutter and detach the rainwater pipe. Ensure that there are no problems with electrics or water.
This is not your average diy project, I would strongly urge you to seek the help and advice of a professional before going on with this.

 

[lostinfens]

duplicated

 

[SFK]

Dear Lostinfens,

With many thanks for your response. And with thanks for the warnings - all will be heeded and it is fully understood that this is a complex. I am getting in a structural engineer to check out some other loadings, so I will also get him to consider this.

I like your method of lifting one side off one wall and leaving the other load on the opposite wall. I will also keep in mind the joining together of the ceiling joist and spar. And then reversing the process. That sounds much more sensible than lifting the whole structure off the walls in one go.

I think first I will try and calculate how heavy my roof is (tiles + joists) so that I can determine who much weight will be on each acrow and I can estimate how many acrows I need.

This is not going to be an immediate job b y any means, but I will try and give an update when I start.

With many thanks again, SFK