relocate rafters to create more space

[rlefig]

Hi I have done some reading in these threads and this is an obvious common question. I want raise a couple of rafters to get a bit more space inside the garage. The garage is old from possibly the 1940's. I live in the northeast and I am conscious of snow load and rake it off if a lot. There are no leaks but again I know the garage is old.

The dimensions are 18' long, 12' wide and 9' high from floor to ridge board. Attached are some pictures. I am going to also have construction friend drop by and take a look. Let me know your thoughts.

Thanks

 

[rlitman]

Those are rafter ties, not rafters.

 

[rlefig]

Ok yes you are correct, Can I still raise these by 1/3 or more and still keep structural integrity? As you can see in one of the pics there are no rafter ties on front of garage only middle on back

 

[rlitman]

Ok yes you are correct, Can I still raise these by 1/3 or more and still keep structural integrity? As you can see in one of the pics there are no rafter ties on front of garage only middle on back

https://www.jlconline.com/how-to/framing/raising-ceiling-joists_o

 

[Dustball]

Yes you can raise them but I would pull the sides of the walls in during the process judging by the visible sag. There's a thread in this section from within the last year of someone doing just that.

 

[rlefig]

Thanks rlitman and Dustball. Dustball when you say sag do you mean sag in the existing rafter ties? If so yes I do see that. Could that be because of the wood and stuff on the rafters? This garage is old and while I do think I will raise the roof one of these years via contractor and shore up the walls I kinda want more space now. But do not want my garage to collapse LOL

 

[fartymarty]

Ok yes you are correct, Can I still raise these by 1/3 or more and still keep structural integrity? As you can see in one of the pics there are no rafter ties on front of garage only middle on back

It looks like it's already under supported. I'm sure that it originally had hinged swing out doors and someone removed the front rafter tie(s) to allow the overhead door to fit. I expect there are some nail holes or other evidence of the removed rafter tie(s) if you search for it. First thing I'd do is see if there is already some measurable* (not just eyeballing it) outward top side wall deflection in the front of the garage halfway between the very front and the first existing rafter tie. If there is then that needs to be fixed first. Perhaps it can be winched in and a double rafter tie installed with enough clearance above door tracks to allow door opening. Then I'd go and install double rafter ties at each rafter (even if it meant adding new rafter ties where there aren't any now) at the new height (1/3 or less).
That's what I'd do, but I'm no engineer.

* Run two taught string lines along each side of the garage the same distance apart at each end and same distance from the floor and then measure to top plate from the string at several locations. Or maybe just use a laser to check for top plate deflection.

 

[rlefig]

FartyMarty you could be correct. The door was definitely an add on. What I want to do is build a golf simulator in there but I need room to swing a club. This whole thing might have to wait until I raise the roof and basically rebuild garage. I have to be careful as I am right on the property line.

 

[rlefig]

How much do you think it would cost to remove roof, raise walls 4 feet or so and construct new roof? The existing roof is old with about 3 or 4 layers of shingles on it

 

[bczygan]

How much do you think it would cost to remove roof, raise walls 4 feet or so and construct new roof? The existing roof is old with about 3 or 4 layers of shingles on it

First, get all that extra weight off the roof!!! There should never be more than 2 layers, usually by law. I always strip, so never more than one layer.

Then yes, you can raise the ceiling joists depending on the size and spacing of the rafters. Always put rafter ties or ceiling joists at every rafter. And rafters should be 2' on center or less. You need to add more.

Bill

 

[rlefig]

Thanks, the whole 1870 house was in very rough shape when we got it and this is the garage is the next step

 

[tyrenta]

My garage looks the exact same and I'm doing the same thing (at a snails pace). Those don't look like joists/rafter ties to me given they are 2x4 but I'm no expert (at all) so don't take any of this as gospel, just what i've figured out here. Check your sills first to be sure they are not rotted, then check walls to see if are plumb. Is there any sag in your ridgeboard? you can look from the outside. if all good then you can tie them 1/3 up. I'm using 2x8 on mine when I finally get it square.

 

[doghouse30]

Hi - see this is an old thread but this is almost identical to what I’m troubleshooting with my old garage, what did you end up doing? And if you shifted the joists up, what approx was the cost?

 

[fartymarty]

Hi - see this is an old thread but this is almost identical to what I’m troubleshooting with my old garage, what did you end up doing? And if you shifted the joists up, what approx was the cost?

What I want to do is build a golf simulator in there but I need room to swing a club.

I'm hoping he gave up golf. Save money all the way around.

(sorry doghouse30, hopefully he, or somebody, will answer you seriously. )

 

[Stuart in MN]

The original poster hasn't been back since Sep 13, 2022 so you may not get a reply...