How can I get more height in this garage ?

maxspeed96ct · Jun 28, 2012

Ok guys, I'll try to explain this as best as I can . This is my buddies garage, hes looking to get more ceiling height (lift install yada yada) .

Below is a pic, I think he has what is called a "gable roof" but im not fimiliar with all of the types so correct me if im wrong . Would it be possible to make safe and code approved scissor truses without ripping apart the existing roof or rafters . Some one told him he couldnt and had to start from scratch ,or add in some type of structial beams , but i just cant see why ??

My idea would be to leave the top portion of the roof and the rafters untouched, and one by one make scissor trusses in each existing rafter .

Is this unsafe or would something be unsupported?

Im not a contractor just trying to give my buddie a second opinion.

Pic of existing .

Here are two pics of scissor trusses I think should be easy to make using his existing rafters and roof. And should be code compliant ?

kbs2244 · Jun 28, 2012

It might be easier to snake in 2 or 3 pre-built trusses than to try and modify in place what is there.
Put them right next to the existing rafters and the remove the stuff hanging down.

You will need them custom built to have a “saddle” for the existing ridge board.

You don’t say where you are and snow load is a big concern with trusses.

I know nobody likes to have inspectors nosing around, but they are a cheap source of things like snow load information.
Or try the local truss dealer.

maxspeed96ct · Jun 28, 2012

kbs2244 said:
It might be easier to snake in 2 or 3 pre-built trusses than to try and modify in place what is there.
Put them right next to the existing rafters and the remove the stuff hanging down.

You will need them custom built to have a “saddle” for the existing ridge board.

You don’t say where you are and snow load is a big concern with trusses.

I know nobody likes to have inspectors nosing around, but they are a cheap source of things like snow load information.
Or try the local truss dealer.

Its in Central CT, so yes so is a concern.

mayday0017 · Jun 28, 2012

Doesn't look like you will gain much height at all but will be lots of work to do it... How much will he gain?

Sef · Jun 28, 2012

I can't really tell from the pics what size lumber is there now, but if your roof rafters are 2x6 or bigger you can carriage bolt in 2x8s up higher.

Basically take the length of your current "ceiling" joist (width of building) and devide it by 3. This will be the length of the 2x8s you will have to put in. Once you tie them in you can remove everything else.

I did this in my house. Went from 8 foot flat ceiling to angled ceilings with a 12 foot high flat center section. The section I did in my house was 27' wide. So devide by 3 and get 9'. So now if you can picture its starting on one wall I have a sloped ceiling for 9' (sloped from 8' to 12') then a 12' high flat ceiling for 9' in the center and then sloped (back from 12' to 8') ceiling for 9'. This was all designed by a architect and approved by code. I did the work myself, it was pretty basic. Bolt new in take old out.

It would basically look like the pic of the first truss you have in you post without the 2 slopped ceiling beams ans supports. The truss are only 2x4 so they need more support but if you have bigger rafters you don't need the extra as long as you use 2x8s.

I don't know what the building codes are like where you are but I'm in New Jersey and they are pretty strict here so I think this would be allowed almost anywhere.

I'll try to find some pics from when I did this to post.

maxspeed96ct · Jun 28, 2012

mayday0017 said:
Doesn't look like you will gain much height at all but will be lots of work to do it... How much will he gain?

Will gain at least 2.5 maybe 3' , makes a differance. But thats why Im asking, just to see if it would be worth doing. Or if hes better of getting a low lift and leaving the ceiling alone.

Sef said:
I can't really tell from the pics what size lumber is there now, but if your roof rafters are 2x6 or bigger you can carriage bolt in 2x8s up higher. Basically take the length of your current "ceiling" joist (width of building) and devide it by 3. This will be the length of the 2x8s you will have to put in. Once you tie them in you can remove everything else. I did this in my house. Went from 8 foot flat ceiling to angled ceilings with a 12 foot high flat center section. The section I did in my house was 27' wide. So devide by 3 and get 9'. So now if you can picture its starting on one wall I have a sloped ceiling for 9' (sloped from 8' to 12') then a 12' high flat ceiling for 9' in the center and then sloped (back from 12' to 8') ceiling for 9'. This was all designed by a architect and approved by code. I did the work myself, it was pretty basic. Bolt new in take old out. It would basically look like the pic of the first truss you have in you post without the 2 slopped ceiling beams ans supports. The truss are only 2x4 so they need more support but if you have bigger rafters you don't need the extra as long as you use 2x8s. I don't know what the building codes are like where you are but I'm in New Jersey and they are pretty strict here so I think this would be allowed almost anywhere.

Honestly I dont know, I hear mixed opinions on my code enforcement. When you say bolt in new and take out old, do you mean remove the existing rafters aswell ?

have any pics of yours during the build ?

Sef · Jun 28, 2012

No, the current rafters stay in place you are just putting in new cross joist (ceiling joist) up higher and taking out the lower ones.

Hopefully my pics work. I always have problems getting them to post.

first pic is before

Sef · Jun 28, 2012

here are 2 more after pics

Nowater · Jun 28, 2012

Call a licensed structural engineer. It looks like the ceiling "rafters" are collar ties that keep the building from spreading apart, but it is difficult to say from the photograph and is true only if the ridge beam is large enough to support the weight of the roof with snow. An Engineer may be able to design a way to "sister in" beams along the ridge and along some rafters so that some of the ceiling beams or collar ties can be removed. Calculations are needed imo.

Falcon67 · Jun 28, 2012

Some notes
1) ceiling joists nailed to the top plates hold the walls together and keep the rafter loads from pushing them out. Remember this when you start taking out framing.

2) Anything lower than 1/3 down from the ridge goes from a "collar tie" to a "rafter tie". Rafter ties ratchet up the load on the rafters and plates, and if you don't take that into the design you can design a building to fail.
http://www.nachi.org/collar-rafter-ties.htm

The best way - as said - is probably to have scissor trusses made to fit, installed and then remove the joist at that rafter. Leave the rafters. To reduce cost, spot where the lift will go and work that area only. No real need to do the whole building IMHO.

maxspeed96ct · Jun 28, 2012

Sef said:
No, the current rafters stay in place you are just putting in new cross joist (ceiling joist) up higher and taking out the lower ones.

Hopefully my pics work. I always have problems getting them to post.

first pic is before

Got um , thats exactly what I was picturing. I'll be sure to show my buddie.

One question though, I see that your insulating . Do you have ridge vents along the outside? will it still get air flow the way you have it done ?

Is this what you have ? Would something like up to the rafter tie be enough air flow?

Falcon67 said:
Some notes
1) ceiling joists nailed to the top plates hold the walls together and keep the rafter loads from pushing them out. Remember this when you start taking out framing.

2) Anything lower than 1/3 down from the ridge goes from a "collar tie" to a "rafter tie". Rafter ties ratchet up the load on the rafters and plates, and if you don't take that into the design you can design a building to fail.
http://www.nachi.org/collar-rafter-ties.htm

The best way - as said - is probably to have scissor trusses made to fit, installed and then remove the joist at that rafter. Leave the rafters. To reduce cost, spot where the lift will go and work that area only. No real need to do the whole building IMHO.

Thanks for the link, that tells me the exact info I was looking for. It makes more sence to me seeing the diagram .

I mentioned to my buddie about only widening in the part that the lift will go, but he was hoping that extra 2ft or so will get a car alittle higher . Which it will but I didnt want to get into details on how much higher....

I'll be sure to pass all the info along and let him go from there, glad its do-able and doesnt sound to costly . He'll be glad to hear it . I think who ever he talked to just wanted to make some money or wanted to take a easier route?

also I forgot to mention, the existing rafters are 2x6 and they are spaced 14" apart .

camarotoolman · Jun 28, 2012

Measure the tallest truck you are going to put on the lift. Add that and the height of the lift. Go up that high and nail in collar ties. Remove whats below the new collar ties. IMo new truss, rafters are over kill. I've been a carpenter a long time. Also you could use the old lumber and save some money. All you will need are some nails.

maxspeed96ct · Jun 28, 2012

camarotoolman said:
Measure the tallest truck you are going to put on the lift. Add that and the height of the lift. Go up that high and nail in collar ties. Remove whats below the new collar ties. IMo new truss, rafters are over kill. I've been a carpenter a long time. Also you could use the old lumber and save some money. All you will need are some nails.

My wife always tells the story of how her grand father would hours straighting used nails and etc .

I definatly agree on saving the wood if possible !

Sef · Jun 28, 2012

maxspeed96ct said:
Got um , thats exactly what I was picturing. I'll be sure to show my buddie.

One question though, I see that your insulating . Do you have ridge vents along the outside? will it still get air flow the way you have it done ?

Is this what you have ? Would something like up to the rafter tie be enough air flow?

Yes, I have a ridge vent and soffit vents with baffles (your pic) and insulation.

maxspeed96ct · Jun 28, 2012

Sef said:
maxspeed96ct said:

Got um , thats exactly what I was picturing. I'll be sure to show my buddie.

One question though, I see that your insulating . Do you have ridge vents along the outside? will it still get air flow the way you have it done ?

Is this what you have ? Would something like up to the rafter tie be enough air flow?

Yes, I have a ridge vent and soffit vents with baffles (your pic) and insulation.

Click to expand...

cool, if you have any more pics of what you've done please share. Seems like you did exactly what my buddie wants to do.

cyamaha2007 · Jun 28, 2012

ive done it before. Ive got a few ways to do it how many trusses do you need to modify?

maxspeed96ct · Jun 29, 2012

cyamaha2007 said:
ive done it before. Ive got a few ways to do it how many trusses do you need to modify?

Id say 10 maybe 12, have any pics you can share ?

Falcon67 · Jun 29, 2012

maxspeed96ct said:
My wife always tells the story of how her grand father would hours straighting used nails and etc .

I definatly agree on saving the wood if possible !

My grand dad taught me young how to straighten a nail and re-use. He'd be mad at the nails I toss sometimes, just because they are so cheap. Don't try it with a gun nail - those don't seem to be good for anything but the first shot.

As long as you don't have a door or other large hole with a header along one wall where the joists sit, you can double a joist here and down there and take out several in between. 10~12' of missing ceiling joists are not likely to bother the walls too much.

The Frisco Kid · Jun 29, 2012

What's this "snow load" that you're concerned with?

:evil:

- from Texas!

NUTTSGT · Jun 29, 2012

Quit looking up for a minute and look down. What's the foundation ? Is it block ? Can you raise the entire structure and lay a few courses of block ?

2 feet in height = 3 courses of block.

Ryf · Jun 29, 2012

to get around the rafter tie issue, box out around the vehicle space the same way they do for stairs (usually requires posts, but if your adding a lift theres already nuisance posts so putting 4 posts just outside the lift area shouldn't be a big issue, plus gives you a surface mount space for outlets and air if you want, if you do it on one wall, you would only need two posts towards the center unsupported space. tie the wall side of the opening to the outer wall and make sure its properly supported (sister in a double support in the wall its attached to to prevent sagging if its a concern)

you will have to go get a inspector/engineer to approve it but its pretty common, my stairs to my basement are done this way and you could fit a car in my staircase, they put stairs into attics with this same method, and I would make sure you describe it as such. you'll also have to make sure you have adequate footing under the concrete for the rafter post.

hope this helps.

Toomanytools? · Jun 29, 2012

Basically you have a hand stacked roof, meaning the ridge was set and rafters laid in by hand then collar ties and ceiling rafters added. You can do as in your first post and build a scissor type truss. The post about moving the ceiling rafter up 1/3 applies. If you needed you could slip an LVL under the exsisting ridge for added strength, but I don't think it is needed. Some DIYer's don't want to get a building inspector or enginner involved because of cost or fear of doing more work or them seeing other none permitted work already onsite. I would find someone you can talk with your local building code guy and show them what you have in mind. Good luck
Oh raising the building way too much labor unless it's an 8x8 shed. I raised a two story house that had a 26' x 38' footprint and added a third floor under it not easy.

maxspeed96ct · Jun 29, 2012

Ryf said:
to get around the rafter tie issue, box out around the vehicle space the same way they do for stairs (usually requires posts, but if your adding a lift theres already nuisance posts so putting 4 posts just outside the lift area shouldn't be a big issue, plus gives you a surface mount space for outlets and air if you want, if you do it on one wall, you would only need two posts towards the center unsupported space. tie the wall side of the opening to the outer wall and make sure its properly supported (sister in a double support in the wall its attached to to prevent sagging if its a concern)

you will have to go get a inspector/engineer to approve it but its pretty common, my stairs to my basement are done this way and you could fit a car in my staircase, they put stairs into attics with this same method, and I would make sure you describe it as such. you'll also have to make sure you have adequate footing under the concrete for the rafter post.

hope this helps.

Ya calling a inspector isnt a bad idea, my buddie is trying to keep the costs minimal though since the lift would be more for personal use rather then a buisness or anything. So he's trying to avoid engineers and etc if possible . And raising the structure isnt a option.

Toomanytools? said:
Basically you have a hand stacked roof, meaning the ridge was set and rafters laid in by hand then collar ties and ceiling rafters added. You can do as in your first post and build a scissor type truss. The post about moving the ceiling rafter up 1/3 applies. If you needed you could slip an LVL under the exsisting ridge for added strength, but I don't think it is needed. Some DIYer's don't want to get a building inspector or enginner involved because of cost or fear of doing more work or them seeing other none permitted work already onsite. I would find someone you can talk with your local building code guy and show them what you have in mind. Good luck
Oh raising the building way too much labor unless it's an 8x8 shed. I raised a two story house that had a 26' x 38' footprint and added a third floor under it not easy.

Sounds good, that ties in with what others have said aswell. A few websites have mentioned the lower 1/3 rule which makes sence to me now after doing some reading. And should he get another 2ft or so of height. Also he should be able to reuse most of the lumber .

I hear in my area the inspectors are big on insulation r value and etc, so hopefully we can squeese some baffles in enough insulation to meet local code specs . But im not sure if they would really be to picky with the r value and etc if its just a garage ?

Falcon67 · Jun 29, 2012

Insulation in a garage is more the exception than the rule. Even new houses around here with blown in don't have any blown over the attached garage. If it's not living space, then it's pretty much off the radar as far as insulation/heating/cooling goes.

Ryf · Jun 29, 2012

maxspeed96ct said:
Ya calling a inspector isnt a bad idea, my buddie is trying to keep the costs minimal though since the lift would be more for personal use rather then a buisness or anything. So he's trying to avoid engineers and etc if possible . And raising the structure isnt a option.

please understand, you dont HAVE to get an engineer involved to box out for a stair case type hole, but you do need to speak to someone who understands basic construction and frame loads, you need have enough post strength to hold it up, and enough beam strength to displace the load, you CAN do it yourself, and IMO this option is alot easier (maybe/ probably cheaper) than trusses, the only issue is you need to know what it will take to carry the displaced load. maybe another way of saying it is, look at some house plans online, and see how they do staircase cutouts, this will give you an idea what I am talking about. if you cant afford an engineer I recommend steel posts, they hold more than wood and you wont have to guess (or risk being wrong) and go up two sizes for the doubled support ring.

the reason I recommended this is you dont have to redesign the trusses, or the attachments for them, you just make a hole, frame it, support it, and your done, make sure the depth of your concrete will hold the weight, if not, cut and pour 2 footers with attach points.

either way good luck

How can I get more height in this garage ?

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