Raise the Roof

[GareyD]

If ya need me, my epuipment, or my tools...give a yell...I'll be there!!!!

GareyD

 

[khd]

Do you need the extra height from wall to wall or would say the center half or so be enough? If so you can gain quite abit of space by re-engineering your trusses right in place as already mentiond. Moving your current ceiling joists up into the rafter to become a collar tie; vaulted ceiling style or even hammer truss style. You may have to sister up beefier rafters as you will lose the "engineered" effectiveness of the current trusses.

Or....Hire a couple of cranes to lift of the whole roof and drop in your pre-fabbed knee walls and set it back down...I have no idea what it costs to have a crane and operator come in though.

Regards,
Kevin

 

[johnday]

Mark; The most important thing here is, DO NOT try modifying any truss without the recommendations from the truss company engineer. Modifying and repairing trusses is not a good thing for joe homeowner, although you might get by with it. Please remember that trusses are an engineered product, that is why the top and bottom chords can be so much less material than a raftered roof. If you plan on a metal roof, strip the shingles and sheathing off trying not to damage the truss. Then you will have a wide open building in which you could build a studwall the height you want. Then reinstall the trusses. Bear in mind though, that trying to save the trusses might be impossible, that is, how are they attached to the top plate? Usually the are just toenailed, and you may destroy them getting them out. Since I mentioned toenailing, that should only be used for temporary attachment. Once you have the roof on, go back and install hurricane ties, these tie the truss to the top plate much better than toenailing. You will use special nails to attache the tie to the truss and common sinkers, usually 10D's to attache to the top plate. There are a number of builders on this site including myself that may offer even more advice. Remeber though, the advice you'll recieve is regional, so check with your building inspector, your paying him for his knowledge and signature on a permit, and it's his job to insure you have a safe and happy building. /forums/images/graemlins/cool.gif

 

[rockinmywaypa]

Lots of good advise here. A short story about a fellow I knew. Found out that a 40 x 100 ft hog barn was being removed in his neighborhood. He managed to buy it for next to nothing then removed steel in two strips so he could cut the prlins from top to bottom with chainsaw,ending up with 3 sections of roof then he inserted long poles into the peak and picked up one section at a time with a crane and set them on flatbed trailers. moved them home and reset them on top of 20 ft poles, then he stood up the original walls out from the roof and joined roof to walls with new rafters. The finished barn was huge especially after he built a loft floor so he could store hay and straw above the livestock. Total costs were not too high since poles came from owners bush and the hog barn was so cheap. Crane was only a couple hours getting old unit down and maybe a day or so back up.

 

[fishman]

I like BCZoom's idea, particularly if the roof sheathing needs replaced anyway. For a minimal amount of money you could have a new looking building. It also seems to me that the truss attachment would be more solid if it were re-attached with approved fasteners to your new, higher walls.

But jacking up the whole roof does sound fascinating. /forums/images/graemlins/smile.gif

 

[mrcaptainbob]

Just did something vaguely similar. The east wall of the barn had a gross sag. Didn't want to lose the whole thing for something that simple. My son came over and we used seven jackposts on that one wall. Raised the whole barn up about 4 inches, the sag part about 7 or better. Knocked out the old rotted basement wall, poured a footing and built a new wall. Set it all back down and now you can drop a marble anywhere on that main floor and it won't roll! The barn is 25 x 35 and we were working the long side. Point is, we had to lift a lot more weight than what you're doing. Jackposts run about 60 or 70 beans apiece. Weld a plate to the bottom so they stand by themselves. Get as many as you need and then a few more. So when you get them maxed out, you block up the extra ones and release the short ones. Keep working around like that. Span as many trusses as you can with some 4/4's. At 40' long, I can see maybe 8 posts/side total of 16 plus the two 'helper' posts. They usually have about a 7" max raise on the jackscrew, so you'd have to keep adding some 6" material to the bottoms to get your needed height. To separate the trusses from the block, use a sawsall between the block and the plate the trusses are on. Toenail the 4x4's to the trusses so there's no movement. Build your little stud walls ahead of time to just pop in when you get the height you need. Make sure to still put in the wind braceing as you would a full sized wall. Lay down that separater strip on top of the block before you set your new mini-walls in place. Use a Hilti to fasten it to the block top. By the way....since your doing this much effort, why stop at eight feet? Consider nine. Once you put up lights and such, the standard length eight foot items will end up clankin' them. ($.02)

 

[MarkV]

Hi All,

Some real good suggestions that brought to mind some points I hadn’t thought of. I thank you all.

A few thoughts in response to some of the questions brought up. Modifying the roof trusses will not accomplish everything I want so that will not work. As the building sets now there is one roll up door that has less than 7’ clearance making it useless for getting any vehicle in. The added height would allow for a header placement higher up and a taller door.

I can see how a crane or moving company could raise the entire roof and make short work of the project. With out pricing things I suspect that the cost of replacing the sheathing and shingles or going to a metal roof would be less than bringing in the big guys though. Of course we are getting close to needing armed guards on lumber delivery trucks with the current prices of lumber so it might be worth a call or two to check.

I am a bit of a stranger in a strange land here, city guy moved to the country, so I don’t have a circle of friends to help and do most of my projects by myself. (That is until GareyD down the road opened his mouth /forums/images/graemlins/wink.gif, Thanks Garey) I should have explained that my mind was trying to come up with a way to do small sections I could handle by myself even though it would be slow. After a bit of a reality check from all of you it makes the most sense to remove the old shingles and sheathing but reuse the trusses. Doing a third or half of the roof at a time I don’t see any reason the trusses would even have to be brought down from the roof. The trusses are currently toe nailed to the top wall plate so a good blade in a sazall should be able to save them. Also I am a believer in metal connection plates so I would use those on a reinstall.

I do have a confession to make to everyone though. I believe I used all of you a bit and I hope you will understand. I told the wife that after consulting the experts here on TBN that to a person the recommendation was to get a larger tractor with a loader capable of raising sections of the roof to the target height. She just rolled her eyes and went about her business. I believe she has gotten wise to me over the years. /forums/images/graemlins/frown.gif

Thanks for all the help and my ears are open to any other thoughts anyone has.

MarkV

 

[Henro]

MarkV,

You might consider using jacks to raise one side of the roof at a time, while leaving the other side(ends of trusses) nailed in place. Not sure if this would work (you would have to take a look at how much truss you have to work with sitting on the top of the wall) but it might be possible.

My thought would be that leaving the opposite end of all the trusses attached to the other wall, you would not have to worry about the roof shifting. You could jack up the one side, install a new 2' section of wall under it. Make sure that 2' section is properly connected to the lower portion of the wall (need extra studs somehow bolted/attached going from floor to wall top to hold everything vertical and make it strong).

Then lower the roof back down on top of the higher wall section on that side, attach it well, and then repeat on the other side...

Trouble is 24" is a lot of vertical lift. Not sure I would attempt that myself...6" maybe...whatever you do make sure you don't get any real strong winds coming up when you are in the middle of the project!

Hope I have not just repeated what someone else said above...

 

[Robert_in_NY]

That would not work without a lot of precautions. When he goes to raise the other side the angle will either push the new wall out or force the roof to slide out. The only way to raise the roof is to do it all at once.

We have done this before on a much larger scale. A tornado touched down and lifted the roof off the machine shops storage building. The building is 40' by 120'. The roof was lifted up and moved just a few feet but not enough to knock it off the building. My cousins move buildings for a living and we had them come down with their crane and lift the roof up so we could reset it. With block walls you can easily knock out some blocks to get steel beams thru to lift off of. However, I would just block up the 2' instead of building little walls. It is only 3 layers of block.

Now if I did not have access to a crane and wanted to build this myself I would go get 10 small hydraulic jacks (the 6 ton models will work fine and not cost you much. build up cribbing and set jacks every 10 foot along the wall. You don't need big timbers to lift every truss as you can let a few hang in between the timbers the jacks will support. The plywood will hold them fine. Then you raise each jack a few pumps and keep working around the room till you get high enough to get your third couse of blocks in. By using blocks you only have to raise 8-9 inchs and lay up the next course of blocks so if something happens the roof will only fall a couple inches instead of a couple feet. It is not hard and will cost a lot less then re-roofing the entire roof (unless it is in need of repair anyway). But the way plywood has gone it would still be cheaper to raise it and and not destroy the plywood even if you want to reshingle. Building a crib for the jacks is easy and shouldn't cost much. Go to your local lumber yard and buy all the bent and twisted 4x4 and 6x6 timbers you can get. You can usually get them for less then half price. Cut them into 2' lengths and build the crib like a kid using lincoln logs. 2 on the bottom and the next two the opposite direction and so on. We had a roof fall down from a heavy snow and we raised it without any trouble. Took us about one day to get the blocking up into the crawl space at the shop and raise the roof. Took us another week to remove all the insulation, build up a couple walls that were tied together to better support the roof and remove all the jacks, blocks and reinsulate. Your job being done by one person could be done in 3 days easily if all you did is one course of blocks a day. Have a helper and you will be done in 2 (or one long day). Just remember, if jacking up the roof the shorter the distance from the jack to the roof the better. If you put a 6' 4x4 leg from the jack to the roof it will tip very easily so crib the jack up as close as you can to the roof and if need be place a 4x4 leg from the crib to the roof so you can lower the jack and crib it up another 6-8 inches.

 

[Henro]

<font color="blue"> That would not work without a lot of precautions. When he goes to raise the other side the angle will either push the new wall out or force the roof to slide out. The only way to raise the roof is to do it all at once.
</font>

Robert,

That is your opinion and I can live with it. However, I wonder if you did any calculations to verify it? Worst case we are talking 2 foot rise over 20 foot of width. Still you could be correct. Like I said I would be more comfortable with 6" lift. But I doubt that if you do the calculations that you will find an extreme level of side thrust resulting from that amount of elevation change...

Still, it would be advisable for anyone who might consider doing what I suggested to calculate things out for themselves and see what is what in their specific situation.

However if one wanted to, I am sure it would not take much to brace the walls from the outside...to prevent shifting...

But even then, who knows? No doubt that lifting the whole thing at one time avoids a lateral push...providing that the lifting setup is rigid...otherwise...you have something moving on its own...inertia at work...could be even worse...

I think a roof that is shifted off its base, like the one you referred to, is a completely different animal than one that is in place and just needs lifted. In that case a crane would be the only way to go.

Anyway, whatever the poster does, he certainly should take precautions to make sure it goes as expected.

The safest way is certainly to take the roof off piece by piece and put it back up after the walls are extended upwards.

Keep in mind that cranes are not a guaranteed safe way to do things either...they fall over sometimes...proven fact.

I can't help to take exception to your statement that the "only way to raise a roof is to do it all at once."

This certainly is one way, but not the only way. Not necessarily even the only SAFE way.

Really, the only way to raise a roof is the way that causes it to happen safely and without incident. And the only way to know for sure that doing it the way one planned is "for sure safe" is after the fact...

Still, in the end I guess I have to agree that 2 feet in 20 is enough to be a concern. But it only equates to 6" in five feet. Thinking about it, I have lifted things five feet wide six inches high, and they sure don't feel like the want to slip out of my fingers horizontally... /forums/images/graemlins/confused.gif Even heavy things...

In the end if I needed to do it, I might try my suggestion. But if anyone else needs to do it, I would suggest you heed Robert's warning...Better safe than sorry... /forums/images/graemlins/smile.gif