Plfking,
How did you determine the angle to cut the base of the mount?
I want to build mounts similar to yours and have not figured out the angle short of building the deck, setting it in place, measuring the angle and then cutting the "feet".
I am sure there is a better way. I have not figured it out.
Thanks.
S.
I thought about building the frame first, but was afraid I'd miss something and end up too long or too short and miss a rib, so I thought I'd mount my 4 supports first, then measure from there for the deck frame dimensions.
I "assumed" the center of my roof hatch was the centerline of the roof. Parked on a level cement floor, marked the centerpoint, then went out 40" to each side (for an approx. 80" wide deck, and marked at 36" and 40" to represent my 4" square top and bottom plates). Laid an 8' length of 2" tube stock across the roof, placed a 4' level on top of it, leveled it by stuffing rags between the tube stock and roof, then measured from the bottom of the tube stock to the top of the roof. I came up with 5" at the 36" mark and 6 1/2" at the 40" mark. I then added 2" to each of those dimensions to give me better airflow under the deck.
With all that said, I screwed up a little anyway. I gave the fabricator those measurements and told him to cut the TUBE that size, when I should have said that the top and bottom of the plates needed to finish at those dimensions.....so i ended up with a little higher angle than planned. My deck will now be 84" wide instead of 80", and since the supports will mount a little lower down the sides of the roof, I'll have to add a spacer to the top of the plates to get me back to that desired 2" clearance.
I'll make it work, but I hope you learn from my mistakes.
1) Definitely should have had the plates made 6" x 4", to give myself more room for boring mounting holes. But 6" may be too long to lay flat enough on the curve of the roof.....I should've taken a scrap piece of wood and experimented.
2) 2" tube stock may be overkill....I think 1 1/2" square would work fine, plus would give you more room on the plates for boring holes.
3) Probably much easier to get your measurements from the very back edge of the roof....less danger of slipping off the roof
, and you'll have a better angle to see everything. To get the centerline, maybe measure across the bus at the top of the emergency door, get the centerpoint, then use a 4' T-square to transfer that point to the roof ?
4) An 8' length of STRAIGHT 2" x 4" would probably 'droop' less than the same length of 2" tube stock.
Sorry for the novel......but do as I say, not as I did.
