I'm building a wood shed....I need some help

General Lee · Dec 9, 2015

Fellas -

I am building a 3 sided wood shed 12x16. Simple one direction slant roof. 10 foot high in the front, 8 foot in the back. Now, I'm fairly decent with carpentry but its the brain work of the laying out I suck at. I have limited time and I tend to rush with things and get over zealous with getting things done with the time I have.

Here is my problem and question to start. I roughly laid out my 6 holes for the posts and dug the holes. I set the first post and its in concrete. I want all posts to be 24'' in the ground. Whats the best way to line all posts up off of the first post so the building is square AND to make sure the same amount of post is sticking up out of the ground so my header board can be perfectly notched and leveled? There will be 6 posts (6x6's). 3 in the front and 3 in the back. I got ahead of myself and I know I will have to adjust the holes some.

I know I will have plenty of questions along the way. I hope you guys are willing to help. This will be a learning experience for me as well because this is my first do it myself project of this magnitude.

Trials · Dec 9, 2015

I built mine out of inexpensive 4x4 P.T. lumber held together with big lag bolts and washers. I laid out a rectangular frame on level ground and made the sides in a post and beam type style construction. a second rectangular frame is at the 8' height cross braced with wire. For the roof I made it in a simple A shaped roof and covered it with corrugated steel just like a barn roof, simple trusses are at 2 food spans. The sides are covered with inexpensive lattice style pressure treated wood. It has no foundation or posts sunk into the ground because I figure it will never blow away when it has all that wood stacked inside it

I've been using it for about 8 years so far.

747driver · Dec 9, 2015

If you have a transit level just make a line on the existing post and then shoot that grade measurememnt onto the remaining posts. Put up batter boards and make string lines for all 4 sides then measure diagonal from each corner to corner until you get the same distance. You can also use the string lines once they are setup and measure using the 3' x 4' = 5' on each corner.

texas42 · Dec 9, 2015

The best way to get it square is use 3,4,5 rule or multiples of it.
3 foot on one side, 4 foot on other side and 5 foot on the angle.
As far as level use a water level. Just google water level. They work great

MossRoad · Dec 9, 2015

texas42 said:
The best way to get it square is use 3,4,5 rule or multiples of it.
3 foot on one side, 4 foot on other side and 5 foot on the angle.
As far as level use a water level. Just google water level. They work great

I had a water level and it worked great. When I broke it, I just used 100' of 1/4" clear plastic tubing. I put a couple gallons of water in a bucket with some green food coloring, siphon the water into the tube until its full, then clamp the ends with alligator clips. Tack one end of the tube at your mark with a staple and remove the clips. Its easy to see the water level from anywhere within 50'. :thumbsup:

General Lee · Dec 9, 2015

Never heard of the 3,4,5 rule. I was thinking of doing the A squared x B squared = C squared.

12x12= 144

16x16= 256
____
400 squared = 20

Then measure 12' and 20' from two stakes until those two measurements cross and then that is my corners?

Unless the 3,4,5 rule is easier and someone wants to explain it

groundcover · Dec 9, 2015

3,4,5 is plenty simple, measure out from one corner 3' and 4' and when you have 5' between those two marks you have a 90 degree corner. Also measure diagonally end to end,should measure the same.

General Lee · Dec 9, 2015

groundcover said:
3,4,5 is plenty simple, measure out from one corner 3' and 4' and when you have 5' between those two marks you have a 90 degree corner. Also measure diagonally end to end,should measure the same.

Ahh so basically its the same as my pythagorean theory above

tbrooks26 · Dec 9, 2015

^^^ right, and your diagonal should be 20'. If you put 2 stakes 16' apart, and then measure 12' and 20' that will give you a third corner

tbrooks26 · Dec 9, 2015

Oh and i would say string line w/ string level wood be close enough for a wood shed, unless your planning on doing something fancy down the road

General Lee · Dec 9, 2015

Yes, I was thinking a string line with a level. And you're right, its just a wood shed doesn't have to absolutely perfect.

Garandman · Dec 10, 2015

General Lee said:
Never heard of the 3,4,5 rule. I was thinking of doing the A squared x B squared = C squared.

12x12= 144

16x16= 256
____
400 squared = 20

Then measure 12' and 20' from two stakes until those two measurements cross and then that is my corners?

Unless the 3,4,5 rule is easier and someone wants to explain it

9+16=25. Same rule, you just multiplied by 4.

GLyford · Dec 10, 2015

Whenever I try it, I never seem to be able to get all the posts set to the same height. My thought is set your posts, hang your header level, then trim whichever post(s) is/are too tall. If you're running rafters and purlins, remember you don't have to cut the posts shorter than the header, just shorter than the top of the purlins, so you have at least a rafter's worth of leeway up and down. I like to run the posts a little tall and bolt the rafters to them too just on principle anyway...

Cord · Dec 10, 2015

The easy way is to set some string lines using stakes outside of the building footprint. Then buy posts that are too long. Set the posts and use some 2x4's and stakes to brace them plumb in both directions. Now pour the concrete taking the time to check the posts for plumb. The next day come back and snap a line at the height you want the posts to be and then cut them off. Might waste 2' of wood, but it's cheaper than buying and setting a new post.

KennyG · Dec 10, 2015

General Lee said:
Never heard of the 3,4,5 rule. I was thinking of doing the A squared x B squared = C squared.

12x12= 144

16x16= 256
____
400 squared = 20

Then measure 12' and 20' from two stakes until those two measurements cross and then that is my corners?

Unless the 3,4,5 rule is easier and someone wants to explain it

(3x3) + (4x4) = (5x5)

Your building is just 4 times this size, so the diagonal is (4x5) = 20, just as you calculated.

BigBoyToys · Dec 10, 2015

I think the method "Cord" described is the best. I just poured a 18'x24' monolithic slab and ran my stakes beyond the outer edges of the perimeter. This way you make your adjustments so the intersections of the strings are exactly at the dimensions you want. Best to just cut the tops of the posts once they're cemented in so everything is at the proper height to be level.

buckeyefarmer · Dec 10, 2015

General Lee said:
Never heard of the 3,4,5 rule. I was thinking of doing the A squared x B squared = C squared.

12x12= 144

16x16= 256
____
400 squared = 20

Then measure 12' and 20' from two stakes until those two measurements cross and then that is my corners?

Unless the 3,4,5 rule is easier and someone wants to explain it

You did a great job explaining it.

General Lee · Dec 10, 2015

Cord's instructions may be the easiest for me to do. Problem is I already bought my posts. 12 and 10 footers. I may be able to return and exchange the 10 footers. Holes are already dug so unless I feel like back filling the holes to get my post height where I need it, I may just exchange them. And once I layout the area again with a string line, I know I will be shaving some holes because I rushed this and they may be off a little.

clemsonfor · Dec 10, 2015

yall totally lost me on that 3,4,5 rule? where are you measureing? diagnal from corners, or toward the other posts?

I would just measure diagonally between posts and then just make my posts taller or close to the height they need be and bolt my headers to them and if too talll cut off the excess. Thats how i made mine. I built a 12x16 woodshed and put it on 4, 4x4s but i put the posts like 8x12 or so and have roof overhanging where the posts are located a good bit to shorten the run of the header as i did not want a center post. We seldom have snow in this area so snow load is about a non existent problem although i did have 5+" of heavy wet snow up there a few years ago with no trouble. My shed is open on all sides though so that i could pull wood from different areas. If i were to do it again i would make three sides probably to keep blowing rain off, but it does help the drying process to not have sides even if you make gaps in the boards. And because i still have roof outside my posts i would have to get creative on how to make the sides now to not loose under roof area.

i think i may add onto one side about 6-8 foot and may make that new section sided when or if i do. But i bought a new metal carpost thats 18x21 for wood so that i dont think anytime soon i need a new addition to the old wood shed.