Adding height to existing garage--lifting the roof?

[Dave88LX]

I was talking with a guy at work today...

He said that you can have a crane insert a long steel beam down the rafters/roof joists perpendicular along the ridge, through the roof, lift the roof off the building, have the carpenters frame the building 4 feet higher, and drop the roof back down onto the structure.

48' x 28', go 4' higher.

How much money are we talking here? Fill me in on any more details, or is that about all there is to it?

 

[Junkman]

Price the cost of a day for a crane, plus the cost of the carpenters, lumber, etc., and you will see that this isn't going to be an inexpensive project. In the end, the money that you save might be better spent having the carpenters lift one side of the roof at a time and build the additional wall. I have seen it done, but it is a lot of hard work. Usually it winds up being less expensive to tear the old roof off, reuse the lumber/trusses, and rebuild.

 

[Dave88LX]

Oh really...the dude at work said the day-crane would be cheaper than rebuilding the roof...

I don't know what either costs to be honest. I would assume the engineered trusses can be reused.

Probably not something that will be very feasible price-wise, so I'll have to stick with 8'. Shame.

 

[IHI]

Big process and not quite as easy as just sticking a steel rod down the center and lifting the roof to construct under.

Have to speak with Planning and Zoning first and foremost to be sure you can raise the roof to the height you plan too.

If they're fine with the new/future height to the midspan point then i would be lining up a crane and scheduling it. most in my area run about $300. $150 to show up and then $150/hr there after.

In the mean time you'd have to go in and cut/detach the rafters/trusses from teh top plate. If you have rafters your going to have to figre out some way to tie them together so they dont spread on you...the roof is designed to take on weight pushing down on the center of your ridge line, it's not designed to take the force of uplifting all that weight up towards the sky.

Removing soffit material, downspouts so the roof is free of the siding related items. Cut holes in the gable ends/roof deck for beam and cables to poke through to attach to crane.

Your going to have to figure out some way to temporarily brace the now lifted roof deck that is suspended in the air so it does'nt come crashing down if a freak accident were to occur so you dont kill anybody.

Then if it were me i would already have these 4' wall sections prebuilt so once roof is up you can have a bunch of buddies help lift it up into place on the original top plate and bang them on with the quickness after you've leveled/squared them. Personally I would also remove 4' of siding down from top plate as well as the wall sheathing so you could then install a row of full sheet plywood around building, helping to prevent the new extension walls from tipping in the event of a big windstorm....

then once that's all accomplished, you can then have the crane lower the roof back into position and reattch rafters/trusses to the new top plate portion.

biggest thing with this project is having everything done and ready to go so your not paying a crane and operator to sit there while you build....lots of prep but i would venture to say an expereinced crew could have the actual lifting, putting premade pieces in place and setting done in under 2 hours tops!! for a DIY, lots more if they have not expereince. You'd better pay a rigging crew too for the actual lift if your on here asking questions...so i would venture to say if you budgeted at least $6-800 for crane service your good depending on your market area.

 

[Dave88LX]

Thanks for the detailed answer! This is something where I would probably completely hire out, even though I hate to do that. I don't have experience building/framing, so it would take me quite some time. My instructions would be "The wall is currently 8', make it 12' so that I can just add full sheets of OSB and drywall, and everything will be uniform" type of thing.

I'm sure that would be a bit more money but I know it would be built right, and probably be done a whole lot faster than I can do it, meaning less crane rental time.

I'm amazed it can be done that fast, but I guess it makes sense.

 

[IHI]

I'm amazed it can be done that fast, but I guess it makes sense.

The actual deed when that takes place can happen fast if the crew knows their stuff, but it's the preparation BEFORE the roof gets lifted off is where there will be some time wrapped up. ALL said and done from start to finish depending on access and what's involved, if i were bidding it time wise i would probably schedule 1.5 weeks to dismantle, build, lift, set, assemble, and refinish.

Your honestly, which you know, are looking at a pretty hefty bill all said and done. I wont guess or hip shoot since your region prices will be far different than mine, but it's going to be spendy...then again, once it's done it's done and it'll probably make life a heck of alot easier/better so i'm sure it'll be worth it in the long run.

 

[jgbrueck]

I was faced with the same decision a few months ago; I have a 30x40 shop in the backyard with 10' ceilings (standard engineered trusses), and I wanted more height. Discussed the option of taking off the roof, etc. Ended up actually have a truss company make me a full set of scissor trusses, then having a roofing contractor come in and "sister" them up to the original trusses, then cut off all the excess underneath. Went from a 10' ceiling all the way around to approx. 16-17' in the center. HUGE improvement; I love it. All told, it was about $2000 for the trusses; the roofing guys had the new ones in in under a day.

 

[tfi racing]

I did some electrical work on a couple of "raised" garages for an old school general contractor,one of them was his own garage.He rented or borrowed some large jacks and cribbing from a house mover,raised the building about four feet,blocked it up for safety and built concrete block walls around the perimeter,then set the building back down on the new block stem walls.He said it was no big deal(at that time,he was close to seventy years old!) and only took him and a labourer or two a few days to do.

 

[IHI]

I was faced with the same decision a few months ago; I have a 30x40 shop in the backyard with 10' ceilings (standard engineered trusses), and I wanted more height. Discussed the option of taking off the roof, etc. Ended up actually have a truss company make me a full set of scissor trusses, then having a roofing contractor come in and "sister" them up to the original trusses, then cut off all the excess underneath. Went from a 10' ceiling all the way around to approx. 16-17' in the center. HUGE improvement; I love it. All told, it was about $2000 for the trusses; the roofing guys had the new ones in in under a day.

This intrigues me, how the heck did they get the scissor trusses up into position with existing trusses 2' o.c. in place, and the more importantly, how did they get the trusses on top of the top plates and into position given the tight nature anyhow....did they just cut the roofing nails from the bottom of the roof deck, or did they pound them up lightly and then go on the roof and pull the roofing nails that enevitably landed where the sister trusses went?

Interesting, just trying to picture who this is even possible given the space allowed, angles invovled and truss placement with everything else involved to pull it off

 

[sparky1562]

IHI, I just did this in my garage. I took out 5 standard trusses and put in 5 sissors like jg suggested.

It you look at the end of the truss over the top plate, depending on the truss, there is probably 6" or more between the top plate and the top chord of the truss at that point. The new sissor truss only needs like 1" of bearing, if you consult the truss company, so the bottom chord lenght can be less than the existing truss. I ended up with around 4" of bearing on each end.

Between the 2ft horizontal, the 6" plus at the plate, it was easier than i expected. I did it myself with no help! (I did cheat and used my tractor front end loaded with a jig on it to lift them up - i am a wimp!). I knocked the roofing nails out of the way first, used a pry bar between the top plate and the new truss to push it up to the underside of the deck, and nailed them together. Then I blocked out under the tail end between the new bottom chord and the top plate and cut the old bottom chord out.

 

[sparky1562]

I did some electrical work on a couple of "raised" garages for an old school general contractor,one of them was his own garage.He rented or borrowed some large jacks and cribbing from a house mover,raised the building about four feet,blocked it up for safety and built concrete block walls around the perimeter,then set the building back down on the new block stem walls.He said it was no big deal(at that time,he was close to seventy years old!) and only took him and a labourer or two a few days to do.

That is how I would have done it, if I needed more space at the edge.

 

[KustomZ]

I did some electrical work on a couple of "raised" garages for an old school general contractor,one of them was his own garage.He rented or borrowed some large jacks and cribbing from a house mover,raised the building about four feet,blocked it up for safety and built concrete block walls around the perimeter,then set the building back down on the new block stem walls.He said it was no big deal(at that time,he was close to seventy years old!) and only took him and a labourer or two a few days to do.

That's what I would too. Might talk to a house mover about raising it for you if you decide on this method. Wouldn't take much if your only raising it 4 feet.

 

[IHI]

IHI, I just did this in my garage. I took out 5 standard trusses and put in 5 sissors like jg suggested.

It you look at the end of the truss over the top plate, depending on the truss, there is probably 6" or more between the top plate and the top chord of the truss at that point. The new sissor truss only needs like 1" of bearing, if you consult the truss company, so the bottom chord lenght can be less than the existing truss. I ended up with around 4" of bearing on each end.

Between the 2ft horizontal, the 6" plus at the plate, it was easier than i expected. I did it myself with no help! (I did cheat and used my tractor front end loaded with a jig on it to lift them up - i am a wimp!). I knocked the roofing nails out of the way first, used a pry bar between the top plate and the new truss to push it up to the underside of the deck, and nailed them together. Then I blocked out under the tail end between the new bottom chord and the top plate and cut the old bottom chord out.

So the manufacturer actually speced the design knowing what was taking place vs just specing a standard scissor truess then is what i'm gathering? rearranged a few board connection points to achieve the space needed to slip it up and in?

 

[kbs2244]

Do a search.
We have talked about the pros and cons of lifting the whole building vs lifting the roof only.
I come down on the side of lifting the building.
All the work is done at ground level.

 

[sparky1562]

So the manufacturer actually speced the design knowing what was taking place vs just specing a standard scissor truess then is what i'm gathering? rearranged a few board connection points to achieve the space needed to slip it up and in?

Yes. It is actually refered to as a scab truss. I took the original truss design to them, and they based the scab truss on it. It was easier than I imagined.

 

[TejasBimmer]

If you do use a crane company, it would be wise to get quotes and an on-site inspection, to make sure the crane can get to your property from their facility.
Good luck!

 

[Shocker]

Hmm. I am not sure you can just add a 4' wall section to the top of the existing wall. it would create a weak spot there at the joint where the 2 sections meet and would scissor under load/stress.

I think your best bet would be to sister 12' boards along side the 8 footers.

I would also look at just stripping the roof off, then removing the OSB (or whatever makes up your roof foundation) then remove the trusses.

OSB is cheep to replace as is the roofing material. you should be able to remove the trusses with no damage. I bet the cost of the crane would be more than the cost of re-roofing.

Then just sister the new 12 footers in there, run the cap and drop the trusses back in. Roof it and done.

 

[toadjammer]

Shocker, Once sheeted with OSB the extensionswouldn't be able to scissor. It may need some tie straps, or to run some pieces of osb down the wall to tie the 4' pieces to the existing walls and then hurricane or truss ties to tie it into the roof again.

 

[randydupree]

i moved a 10'X20' concrete block building,on a cement poured slab 600'.jacked it up,and pulled it with a wrecker,rolled it on pipes,my buddys helped on the pipes,i did all the rst by myself.
jack the building up,its easy.

 

[Shocker]

Well, that might work, but here in my area, that kind of addition is not allowed. Might have more to do with earthquake requirements.