I need to build an arbor between my garage and my house and I need to
know how to line up the beams so they are perpendicular to both
buildings. They are 15' apart and they are parallel with each other,
but one is set back from the other, so I can't just measure from the
end. All I am coming up with is the 3-4-5 rule, but I doubt I will be
accurate enough with that. Any ideas?
P.S. I hope this is the right forum for this question.
Double the numbers to 6/8/10 and it will be twice as accurate. :-) If you
get one beam perpendicular to a building, you can measure from it to the
next beam. At least that's how it seems to me.
How about 15-20-25 ? Use a laser pointer or pull a string straight across
the facing of the building set back to get a beginning reference mark on the
opposite wall. You can tack up identical spacers projecting from the face to
clear obstructions (down spouts etc.) and deduct the size of the spacers to
get the corner reference. Measure the cross beams location from the setback
corner and the reference line on the perspective walls. A level or plumb bob
can elevate your reference line.
I saw an interesting item on TV where they were building houses on floating
barge hulls to make boat houses. The hulls were in constant motion so levels
were of no use. To keep everything level they had to use measurements and
large oversize squares cut from full sheets of plywood. Find a sheet of
plywood, check it for squareness (they usually are) and cut a large triangle
4' x 8' out of the sheet. Cut the center out to lighten the weight if you
want and use it to check your squareness between the buildings.
You can construct a beam that's exactly perpendicular to both buildings
only if the two buildings are exactly parallel to each other.
Since "exact" is never attainable, you might want to ask yourself what
accuracy you really need. Also, a 3-4-5 triangle scales perfectly to a
9-12-15 one. If you do that at each end of the smaller building [probably
the garage] and hang string between them you'll get good baselines from
which you can measure. A framing square should be used as a final check.
Don't expect perfection, you probably don't need it.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.