Garage (err...boatshop) Renovation Question

[Ethan]

Hello all,

My apologies to anyone who thinks that the subject of this thread belongs in another section, but I'd really like the input of everyone, including those not inclined to look in the bilge.

Here's the situation: We have an old garage building on our land that was built by the previous owners. I'd really like to use it as a storage building, overflow boat barn, lumber storage, etc. It's stick built with 2x4's 16" o.c. on a 6" slab. The building measures 30'x50' and has trusses that provide for clear span across the 30' width. There are no interior walls. The shingle roof is coming off (it leaks) and the roof underlayment is going to be replaced during that time.

My question is this - is there any practical way to increase the wall height from 8' to 12' while we have the roof off? By practical, I mean something other than tearing down the walls and reframing with 12' studs. I'm inclined to think that reframing is the way to go, but figured I'd ask since I don't have much experience along these lines.

Any input or ideas will be gratefully received.

Thanks in advance for your thoughts,
Ethan

[Paul Girouard]

So you mean taking the roof truss off the top plates , and framing new "pony walls" 4 foot in height on your existing 8 foot walls ?

You'd have a major hinge point , the old carpenter in me sez your could every 4 feet , beside a existing stud run a 4x4 from the existing bottom plate to the new top plate , strap that with some" Simpson "over the top, down the post strap and be good .

The new engineered stuff we do sez that won't cut it . But bumbel bee's can't fly either, if you ask a engineer.

Local codes might also be a issue .

It can be done , I'm sure, cost / codes / etc are the hurtles .

Good luck , Paul

[Ethan]

Hi Paul,

Thanks for your thoughts - I hadn't considered the 4x4 solution.

"HINGE POINT"! Exactly the concept I'm concerned about, but couldn't find the words to adequately describe - thanks!

[Scott P]

Another possible solution is to have a house moving outfit install some steel beams under your trusses and raise your roof and walls 4 feet then pour a four foot concrete stemwall on your slab. Done this a few times and its not difficult but is not inexpensive.

[Puka]

Depending on the load bearing capabilities of the trusses (if large centres-say 10')I would consider sitting each truss end on a 4x4 SHS
set into the slab (with a footing) creating a portal out of each post-truss-post unit.(inside existing wall) This would brace the structure parallel with the trusses.Then frame above existing wall to new truss height tying framing to steel portal legs .Brace with ply on framing to cater for extra stiffness required 90deg. to trusses.Get an engineer to do the numbers for your wind/earthquake zone, raise it and plead ignorance.(Say it has always been like that or you were just doing roof maintenance) :cool:
Always keep the numbers as back up ammunition and peace of mind that it aint going to fall on your, err, boat.
(may be hard work if your slab has substantial perimeter footing but nothing that a diamond saw
won't deal with)
PS..You dont need to do the ends as they brace each other, just the intermediate long wall trusses. (4 @ 10' cntrs)

[ 01-22-2006, 04:03 AM: Message edited by: Puka ]

[Ron Carter]

Raise the whole building 4' and put 6 rows of cement block around the perimiter. A building mover can raise it relatively inexpensively if you don't have the equipment to do it your self.

Should be structurally sound. Check for local building codes so you don't have to do it twice.

[Mike Vogdes]

By the time you figure in the costs of modifying the building to achieve a 12' wall height, you would be better off knocking the whole thing over and building a new structure to the height you want. Maybe a pole barn type structure would be an alternative, reusing the trusses.

[Roger Cumming]

As an architect, I hesitate to make suggestions without knowing more about the structure. However, one possibility for saving the existing stud walls might be to raise each roof truss (after stripping the sheathing) and adding a new 4-foot vertical member and a new diagonal member to the end of each truss to connect to the top of the 8-foot high stud wall. The additional 4 feet of wall would not be load bearing. The roof load is thereby still brought down to the top of the 8-foot wall as before. An engineer could advise you as to the size of the two new members in each truss and the proper connections to make - metal connectors, bolts, etc.

You should keep in mind that these light roof trusses are very "floppy" and unstable until the roof sheathing is installed. Therefore, lateral bracing and the construction sequence are crucial. You may have to remove the existing sheathing gradually as each truss is raised, altered and each bay is sheathed, rather than doing it all at once. This is where the engineer would earn his fee.

Also, the ability of the entire building to resist wind load is provided by the plywood wall sheathing (or diagonal braces) as well as by the roof sheathing. You should be very careful when altering these elements so as not to set up the conditions for a collapse.

[Peter Malcolm Jardine]

I like the idea of lifting the whole building, if it's sturdy enough. You have to cut the bolts holding it to the floor, and put beams across the bottom to hold the walls together, but it would be pretty straight forward I think. As Ron says, six courses of block and there you are. If you run beams down the length of the trusses and jack from there, the weight is the roof, not the walls.

[ 01-22-2006, 06:20 PM: Message edited by: Peter Malcolm Jardine ]

[Paul Girouard]

Originally posted by Peter Malcolm Jardine:
I like the idea of lifting the whole building, if it's sturdy enough. You have to cut the bolts holding it to the floor, and put beams across the bottom to hold the walls together, but it would be pretty straight forward I think. As Ron says, six courses of block and there you are. If you run beams down the length of the trusses and jack from there, the weight is the roof, not the walls.You'd be asking a lot , more than there is in holding strenght of the nail even with hurricane ties to lift the walls with the roof . Bad Idea IMO . If your going to lift a building like this

a 2 x8 or so sandwich one out side the 2x4 wal one inside thru bolted with long beams under those bands would be the way to go .

If I where doing it , I'd strip the roof of shingles , then start from the top down removing the sheathing , add 1x4 temp bracing on the way down , then I'd lay the trusses down one at a time . Pile then up on one end , frame my pony walls and add the 4x4's to 1/2 or more then hump the truss's up on the new walls , complete the pony wall stuff , restand the truss's , re sheath the roof , I'd put some windows in the pony wall area to bring light in , like a clear storey .

Ya to simple :rolleyes: make it as hard as you like arch / engineers , HOY VEY. Good luck , go Seahawks smile.gif Paul

[Bob Smalser]

Better go hire a local structural engineer to come take a good look. Hard to be rosy about this with only 2X4 studwalls supporting such a large roof load and span in, or close to, hurricane country. Agricultural buildings in many rural states don't fall under building codes and some I've seen are downright scary.

What kind of sill? 2x4 P/T bolted to the slab? Complete studwall atop it or did the builder use the sill as the studwall sole? Is it really just a 6" slab or are more substantial edge footings integral to it? Dig down along side the concrete and see...more height equals more load.

How does this "old" structure obtain its sheer strength? 1X4's let into the studs on the diagonal, 1X6 diagonal sheathing, or plywood sheer walls closely nailed?

You get my drift. Without a detailed analysis and running the strength numbers nobody knows what you safely can or can't do....let alone whether the final result'll meet today's codes.

[ 01-22-2006, 06:52 PM: Message edited by: Bob Smalser ]

[Paul Girouard]

Bob it's a 30 x50 building , 2x4 const . in Alabama . Ya hire a team of eng. bring plenty of $$$ It might need a IBWP , or two but all in all it would be sound with 4x4 post at 4' oc , from plate to plate . Yes if Katrina came down to pipe it and just about everything else around it would be gone as well.

Around here I'd hire a eng. " No other way around it ". Codes , new codes old codes, more codes than you can shake a stick at. Might be the same in Alabama , don't know.

Another thing you touched on P/T plate , this new stuff is eating 1/2" foundation bolts , and Galv. nails .
We may go to cedar sill plates as with TJI hangers on this new ACQ plate stock they are not ZMAX , yet . And like I said , the ACQ stuff is eating metal . So much for better stuff.

Go Seahawks smile.gif Paul

[Bob Smalser]

Originally posted by Paul Girouard:
Ya hire a team of eng. bring plenty of $$$ When you need one on Whidbey, my retired but still certified structural engineer in Bremerton works for 40 bucks an hour plus travel.

Cheap at 3 times the price if you are about to do something dumb.

[Paul Girouard]

Originally posted by Bob Smalser:
</font><blockquote>quote:</font><hr />Originally posted by Paul Girouard:
Ya hire a team of eng. bring plenty of $$$ When you need one on Whidbey, my retired but still certified structural engineer in Bremerton works for 40 bucks an hour plus travel.

Cheap at 3 times the price if you are about to do something dumb.</font>[/QUOTE]Eh Bob I don't do dumb , can't GESTAPO , building dept. is here to stay . We use a guy from South Whidbey , Jack's his name.

Here on the net folks ask for advice some is good most is bad . Situations are not detailed , view this post, LOL . As an architect, I hesitate to make suggestions without knowing more about the structure. However, one possibility for saving the existing stud walls might be to raise each roof truss (after stripping the sheathing) and adding a new 4-foot vertical member and a new diagonal member to the end of each truss to connect to the top of the 8-foot high stud wall. The additional 4 feet of wall would not be load bearing. The roof load is thereby still brought down to the top of the 8-foot wall as before. An engineer could advise you as to the size of the two new members in each truss and the proper connections to make - metal connectors, bolts, etc.

You should keep in mind that these light roof trusses are very "floppy" and unstable until the roof sheathing is installed. Therefore, lateral bracing and the construction sequence are crucial. You may have to remove the existing sheathing gradually as each truss is raised, altered and each bay is sheathed, rather than doing it all at once. This is where the engineer would earn his fee.

Also, the ability of the entire building to resist wind load is provided by the plywood wall sheathing (or diagonal braces) as well as by the roof sheathing. You should be very careful when altering these elements so as not to set up the conditions for a collapse.[/QB][/QUOTE]

Now there's a quack answer.

Seahawks lookin good smile.gif Paul

[Puka]

the ACQ stuff is eating metal Our building authority stipulated hot dipped galv. for structural bolts in CCA timber.(slathered in grease) When they were not correctly installed they figgered they would make us use stainless.
More idiot proof they figgered.
Wonder when they are going to get their first case
failure with crevice corrosion from a "buried" bolt? :confused:
Hell my galv keelson/floor bolts lasted 35yrs pretty damn close to the "marine zone"!
The compliance knee-jerk juggernaut rolls on............

There is "x" amount of risk in life that is impractical to remove.

[ 01-22-2006, 09:52 PM: Message edited by: Puka ]

[Paul Girouard]

Originally posted by Puka:
[QB:

There is "x" amount of risk in life that is impractical to remove.[/QB]So image a wooden boat built by a engineer that insured it would not fail in a storm , hurricane force winds , heavy seas , not knowing who the Skipper / Captain would be? Ark like , as in Noah's , fun to sail??

This shop can be extended to 12' with little issue's , unless you make them issue's .

Hell we'd never build anything if we thought about all that could go wrong .

It ain't rocket science , Paul.

[Puka]

Too right,Paul. Hell be no fun anyway.
My boat repair shed is 15m x 7m x 6m high built
from 4x2 posts (x2ea.) & DIY trusses, curtainsider walls. It could be blown away but its what I got.
If the sat. map looks bad enough I will take precautions...

[Paul Girouard]

Originally posted by Puka:
Too right,Paul. Hell be no fun anyway.
My boat repair shed is 15m x 7m x 6m high built
from 4x2 posts (x2ea.) & DIY trusses, curtainsider walls. It could be blown away but its what I got.
If the sat. map looks bad enough I will take precautions...My god man 50' x 23' x 20' . Enormous smile.gif Hey larger than my shop 40'x 30' x 10'4" . but still workable . Hey my truss's are stamped or at least came from a truss compny still in business. Not that that would matter if the 1990 100MPH wind had blown them off. Chicken little , EH ;)

Only 300 sqr. feet smaller , I like that better than the cubis ft # ;) And I'm thinking about adding on smile.gif Paul

[ 01-23-2006, 02:51 AM: Message edited by: Paul Girouard ]

[Figment]

Originally posted by Roger Cumming:
As an architect, I hesitate to make suggestions without knowing more about the structure.... As a fellow architect, I think it's somewhat reckless to suggest any modification at all! ;) I wouldn't touch this one with a ten foot pole.

In all seriousness, unless this old garage building has some great emotional or historical value to the site, I'd say knock it down and start fresh.
Any of these cobbled-together solutions can work for a while, but I can't see going through such effort for a band-aid.
From a standpoint of longterm value, I doubt that any "renovation" approach to this problem will stack up against putting up a new structure that's exactly what you want.

[scraper]

I've lifted a few buildings/homes in the past. For peace of mind have a qualified structural engineer involved.
Recently I visited with a friend who had his trusses re-engineered to gain more ceiling height. He went from 12' to 14' clearance in the center. Maintiaining 12' near the sides till about 8' out.
It looked over engineered and probably was expensive but he got what he wanted. Having not been in the building beforehand he now had columns 8' from the wall as well - doubt they were original.

[Puka]

I change engineers every few years as the CPPP (creeping pervasive professional paranoia) sets in.I like the "can do" ones. If its outside the tables, sure get some relevant numbers done but lets not get bogged down.Hey and if the signs are right , why not borrow the neighbours geotech report. ;)
I don't think this is negligence;Its a commercial reality. If you want the average family to have a house.

BTW-I have been accused of being pedantic and over-building by clients. Each stuation on its own merit.

[Vince Hoffmann]

As a fellow architect, I think it's somewhat reckless to suggest any modification at all! ;) I wouldn't touch this one with a ten foot pole.

As (another) fellow architect, I agree. But if you insist on pursuing this substantial structural modification, you will need a building permit, and the plan checker / building inspector will require structural calculations to prove that your modifications are sound.

The trouble you can get into without a building permit far outweighs the time and expense of getting the proper permits and designs.

[Ethan]

Greets,

Thanks to all who have shared constructive thoughts, both in the thread and privately.

Upon consideration, I've arrived at a conclusion that's alluded to in several posts - it really is easier and more "future-proof" to just reframe with the wall height I desire. That way, it's right, it's tight, and there's no extra concern if I decide to use this building as my main workshop someday. After running the numbers, it really amounts to pennies for a huge return in peace of mind.

So, we're planning on a 12' eave height using 2x6 studs 16" o.c. The cost should be minimal since we were going to have to replace the roof anyway and we'll be reusing the trusses.

Thanks again to everyone who contributed to the discussion - your input helped me think it through and put things in perspective.

regards, Ethan

[Stephen Hutchins]

If that were my building, I'd sister frame studs along the inside of the existing wall, and put windows along the 3 1/2" x 4' high gap around the outside perimeter.

[TomMcKinney]

You could re do the roof with Gambrel trusses to raise some of the interior hieght,--might be able to re use some of the old truss wood and save some $$$. By first changing every other truss you should keep the buidling intact with little problem.

[Dale R. Hamilton]

I think best way is to keep the existing shop and build a 30 x 60 x 20 enclosed pole barn attached. That way you could use the lower building as the shop and the high ceiling building as the vehicle assembly bldg (just like NASA). Believe this would be MUCH CHEAPER in the long run and you would have one hell of a shop.

[michigangeorge]

a big ditto to Dale's comment! Makes far more sense if you have the room.

[Ethan]

Very interesting ideas - some seem more practical than others.

Luckily, I have no code considerations to worry about. None. Nadda. Having said that, if this is worth doing, it's worth doing right.

TomMcKinney- interesting idea. However, and please correct me if I'm wrong, I believe a gambrel truss over a clear span area requires a horizontal tie between the two walls, no? If I'm correct, all the gambrel style roof would get me is increased attic space, not increased ceiling height over the workshop area.

Dale - interesting thought. That would definitely be a mongo shop. Alas, I think "much cheaper" is a stretch. I can reframe and re-roof the existing building for little more than the 30x60 slab alone would cost me. But again, I like the way you think!

[Puka]

Luckily, I have no code considerations to worry about. None. Nadda. I applaud that attitude :D
Here you need permission to fart on your own land.

Steel SHS portal legs with pony walls has got to be the cheapest option;But it does depend on the nature of the existing trusses to be viable.(centres,construction) & bloody strong!

[ 01-26-2006, 02:12 PM: Message edited by: Puka ]

[Dale R. Hamilton]

Ethan- Actually you would not need a slab in your vehicle assembly building- A good many boat shops use just sawdust. You do need a slab in your carpenter shop- and you already have one. A pole barn sheathed in steel in the cheapest permanent shelter you can build. Insulate it and add a heating/cooling unit and your in. Come see mine just outside Nashville, Tennessee.

[Ethan]

Dale, you're a bad influence, my friend! Thanks for the generous invite - I may just take you up on it.

Does anybody know if saw dust attracts termites? Or, do termites prefer solid wood?

And snakes....

[homeline]

Hello Ethan. It's been a long time since I poked around this site. I,too am thinking of a way to modify an existing building with 8' walls to have a taller ceiling height. I have a nicely equipped workshop now , but have no room to rehab my old runabout. So, the wife and I just two weeks ago bought the house across the street to convert into a workshop. It's a 28'x48' with a basement.

So far, my idea is to modify the extisting premanufactured trusses by making them into a raised tray (or coffered) type. They are 24"oc with a 5.3/12 pitch. This won't do anything in making the sidewall height taller, but will give me 9'-10' for a good portion of the 28' width. I can then easily have an opening in one or both of the gable ends to utilize the added height.

I've bounced this idea off a couple contractors, and they agree it should work. With some barcing and support, I can do one truss at a time with little chance of upsetting anything structurally.

Hope this gives you some food for thought.

Cliff

[Shaver]

Why not make up some 4' stud walls to the same design as your 8' then to avoid the "hinge" problem stagger them one top one bottom. Then 2 of 4x2s about 8' long 2'6" in ground 4' for height 1'6" either side of existing and bolt thru. In the 4' height cut a couple of bits about 6" and put them between the uprights and bolt thru again. If you can't get in the ground cut off the 4x2 1'6" above the ground and bolt thru top and bottom. I don't know how to draw stuff on here otherwise I'd send you a sketch.