Mezzanine Garage Floor Design - Help
Discussion
I've got a decent sized out building, it's 4.5m x 9.5m internally. As part of my drive to reduce clutter I want to add a pair of mezzanine floors, one at each end. Once I get everything stored out of the way I can look at bringing down the dividing wall and sorting out the floor.
The roof construction is ridgeboard, two purlins running the full length. There is a tie beam across the middle at wall-top level and then two 'A' frames that are 2.5m and 3.5m from each end respectively.
The plan is to build the mezzanine floors between the end wall and each A frame, so I've got the full height in the middle, but good storage at each end. There will be a cut-out in each to allow personnel access via a ladder and also a larger access hatch. Plan is that this bit can be lowered with a winch that I picked up on Gumtree, so I can easily lift large/heavy bits of kit up for storage. One end will house my collection of bikes, the other my collection of bits of wood and my occasional tools like my lathe, thicknesser etc. I'd guess storage weight in the 200 to 400kg range, plus the weight of the structure.
Some pics of where we are starting from:
DSC01019 by paulrockliffe, on Flickr
This is the wider of the two bits that will have the floor above. The wall to the left is coming out, it's not structural. The A frame is behind the wood and rests on the two external walls.
These two pics show the A-frames quite well:
DSC01020 by paulrockliffe, on Flickr
DSC01022 by paulrockliffe, on Flickr
And this picture shows the interaction between A frame and wall:
DSC01021 by paulrockliffe, on Flickr
It's not my area of expertise, but I have an OK grasp of the mechanics of the roof. I think. The purlins take the weight to the outer end walls. The A-Frames stop the purlins from sagging and take some load to the front and rear walls. Both the A frames and the tie beam allow the forces pushing the front and rear walls outwards to cancel each other out, so the walls take only a vertical load.
The distance to the ridge board from the lower beam of the A frame is about 1.5m. The span brick to brick is 4.5m The Purlins, A frames etc are roughly 9" x 3" pitch pine. The tie-beam is something like 6" x 3".
My provisional, uninformed, initial idea is to:
1. Sister up the lower beam of the A frame.
2. Attach a matching beam to the outer wall.
3. Use joist hangers to span between beams at about 50cm intervals.
4. Double up the beams around cut-outs.
5. 18mm chipboard floor on top, plasterboard underneath.
My instinct is that 8" x 2" joists would do the job.
Questions are along the lines of:
1. Does the sistered beam need to sit on the front and rear walls or is it just providing additional resistance to deflection of the beam? If it doesn't sit on the wall, can I sister it on the opposite side of the beam?
2. How should the matching beam be attached? Big screws and plugs, frame fixings or resin anchors? How many fixings?
3. intervals appropriate? 40cm better?
4. Is doubling up the beams about right, or would more be needed?
Is the timber about right size-wise?
Something along these lines:
Untitled by paulrockliffe, on Flickr
Obviously, please shout up if there's a better way, or if there's a glaring misunderstanding that's going to cause me problems with the way the roof is dealing with the loads.
Thanks!
The roof construction is ridgeboard, two purlins running the full length. There is a tie beam across the middle at wall-top level and then two 'A' frames that are 2.5m and 3.5m from each end respectively.
The plan is to build the mezzanine floors between the end wall and each A frame, so I've got the full height in the middle, but good storage at each end. There will be a cut-out in each to allow personnel access via a ladder and also a larger access hatch. Plan is that this bit can be lowered with a winch that I picked up on Gumtree, so I can easily lift large/heavy bits of kit up for storage. One end will house my collection of bikes, the other my collection of bits of wood and my occasional tools like my lathe, thicknesser etc. I'd guess storage weight in the 200 to 400kg range, plus the weight of the structure.
Some pics of where we are starting from:
DSC01019 by paulrockliffe, on FlickrThis is the wider of the two bits that will have the floor above. The wall to the left is coming out, it's not structural. The A frame is behind the wood and rests on the two external walls.
These two pics show the A-frames quite well:
DSC01020 by paulrockliffe, on FlickrDSC01022 by paulrockliffe, on FlickrAnd this picture shows the interaction between A frame and wall:
DSC01021 by paulrockliffe, on FlickrIt's not my area of expertise, but I have an OK grasp of the mechanics of the roof. I think. The purlins take the weight to the outer end walls. The A-Frames stop the purlins from sagging and take some load to the front and rear walls. Both the A frames and the tie beam allow the forces pushing the front and rear walls outwards to cancel each other out, so the walls take only a vertical load.
The distance to the ridge board from the lower beam of the A frame is about 1.5m. The span brick to brick is 4.5m The Purlins, A frames etc are roughly 9" x 3" pitch pine. The tie-beam is something like 6" x 3".
My provisional, uninformed, initial idea is to:
1. Sister up the lower beam of the A frame.
2. Attach a matching beam to the outer wall.
3. Use joist hangers to span between beams at about 50cm intervals.
4. Double up the beams around cut-outs.
5. 18mm chipboard floor on top, plasterboard underneath.
My instinct is that 8" x 2" joists would do the job.
Questions are along the lines of:
1. Does the sistered beam need to sit on the front and rear walls or is it just providing additional resistance to deflection of the beam? If it doesn't sit on the wall, can I sister it on the opposite side of the beam?
2. How should the matching beam be attached? Big screws and plugs, frame fixings or resin anchors? How many fixings?
3. intervals appropriate? 40cm better?
4. Is doubling up the beams about right, or would more be needed?
Is the timber about right size-wise?
Something along these lines:
Untitled by paulrockliffe, on FlickrObviously, please shout up if there's a better way, or if there's a glaring misunderstanding that's going to cause me problems with the way the roof is dealing with the loads.
Thanks!
Bump for the day-time crowd.....
I'm thinking this:
Untitled by paulrockliffe, on Flickr
Might be a better layout, basically turn the access gap 90 degrees so it's crossing fewer joists. It's wider in the second example, but that's not deliberate.
I might do it wider and have all my bikes on top of the 'hatch' so they can all be lowered out of the ceiling at once, but as height is tight (about 1.5m to ridge) I won't know the best way to do that until I've got a few joists up and can work out how best to make the bikes fit.
Anyway, advice please?
I'm thinking this:
Untitled by paulrockliffe, on FlickrMight be a better layout, basically turn the access gap 90 degrees so it's crossing fewer joists. It's wider in the second example, but that's not deliberate.
I might do it wider and have all my bikes on top of the 'hatch' so they can all be lowered out of the ceiling at once, but as height is tight (about 1.5m to ridge) I won't know the best way to do that until I've got a few joists up and can work out how best to make the bikes fit.
Anyway, advice please?
Maybe, I can't do Sketchup very good though!
Basically I want to span from the wall on the right of the first picture, to the A frame 3.5m to it's left. The rest of the post was just padding and rough ideas. The Paint diagram is the layout of 8 x 2 joists.
If I get time to workout Sketchup I'll try to get a proper diagram....
Basically I want to span from the wall on the right of the first picture, to the A frame 3.5m to it's left. The rest of the post was just padding and rough ideas. The Paint diagram is the layout of 8 x 2 joists.
If I get time to workout Sketchup I'll try to get a proper diagram....
The lathe weighs 30kg max, there's nothing hugely heavy to go up there. There's 1.5m headroom at the apex, so the volume is never going to be enough to get any serious weight up there, especially if I put 10 bikes up there, that would be 80kg taking up most of the space.
Good point re the lintel over the window - There isn't one, it's a solid wood frame that does the job of the lintel. I hadn't considered that, but if the beam wasn't fixed to the wall above the window, all the load would be transferred to the brick either side of the window, which is the job that the lintel would do. I think.
I should have said, I was hoping to glean enough knowledge to put together a decent design, that fits my needs, before sending it to my brother who is a civil engineer to check over.
Good point re the lintel over the window - There isn't one, it's a solid wood frame that does the job of the lintel. I hadn't considered that, but if the beam wasn't fixed to the wall above the window, all the load would be transferred to the brick either side of the window, which is the job that the lintel would do. I think.
I should have said, I was hoping to glean enough knowledge to put together a decent design, that fits my needs, before sending it to my brother who is a civil engineer to check over.
Tommy Walsh did a series on Discovery, called something like "build my shed" in which he had a mezzanine floor that went up and down hydraulically. IIRC there was about 1metre headroom when the floor was down and 2m when up. So when he was working in the shed the floor was up, when he was relaxing with a beer and the TV the floor was down. Seemed a really good solution. I'm sure someone will be along soon to tell you the proper name of the programme and how to find it.
Tada, found it.
https://www.youtube.com/watch?v=MUAX4uQV_o8
Tada, found it.
https://www.youtube.com/watch?v=MUAX4uQV_o8
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