First time building a shed... and I've got problems.

[KPtexan05]

This is my first time building a shed, and I've encountered some issues I need advice on. This is just an 8'x8' shed, so nothing too big, but it's become more of a project than I anticipated.

I had a slab poured for it while I was having some other concrete work done and, although I knew it was slightly off level, I didn't think it would cause any major issues. This was not a very smart choice because it would have been much easier to correct this before construction.

What I've found is that the back side of the shed (opposite of the door) sits about 3/8" low (that back wall looks level left to right, but the whole thing needs to be lifted by 3/8" or so). The biggest issue is that there's a dip right in the center of the slab where the door is, and it's causing the bottom of each side of the door frame to sit about 1/4" low - this causes a significant issue with the door frame being out of square and I know this because I've cut the door hole in the siding panel perfectly square.

In any event, I believe some shimming may be in order to correct these problems. I have a double sill plate - the first plate is treated 2x4 with seam seal between it and the slab. I made sure this was perfectly square on the slab by taking diagonal measurements and then put the prebuilt walls on top of that.

How do y'all think the best way to level this is? I was thinking about lifting and shimming either between the bottom sill plate and slab, or between the two bottom plates at each stud. Then I could go back in with a grout bag and mortar mix to seal that gap. Does that sound like a workable plan?

Thanks for the help!

 

[Moss]

I can't fully understand your issue but I will say your measurements of 3/8" & 1/4" really shouldn't cause any real problems. I'd be shocked to find a shed that was much more accurate then that. Are you worried about the door installation not going well? What are you concerns?

 

[KPtexan05]

That door frame is being pulled out of square due to a dip in the slab right in the center - I say it's 1/4", but that's at each side of the doorway, so it's probably 3/8" or more dip right at the center. I've got that one panel hung with the side perfectly flush and square to the side of the doorway, and the center of that panel is hanging down about 1/4" into the center of the doorway at the top.

I thought for sure I messed something up in my framing measurements, but I went back last night and rechecked everything. All cuts are within 1/16" tolerances and board placement is no more than 1/8" out on any board. Then I put a level on each side of the doorway on the sill plate, and each one definitely slopes down towards the center of that wall.

But maybe I don't need to go through the trouble of leveling that back wall and the rest of the shed then if 3/8" drop over 8' is OK? It's a completely separate issue from the front wall/doorway level issue. I just want my door to be square and not run into any problems there.

 

[73fxe]

"It's a shed, not a grand piano." As my dad used to say.

 

[JohnX14]

For a shed you could leave the back wall a little low, or shim and grout it, or shim your rafters. Any of those should be acceptable for a shed like this. With the door, I assume your rough opening is oversized, and you will install either a bought or home made pre-hung door and shim appropriately (Including under the threshold if necessary, then trim with casing. I don't see any real problems here.

 

[cgrutt]

Not sure if I understand problem but couldn't you just put a prybar under low spot and shim it? Shoot some spray foam under gap or stuff with backer rod and use a good caulk/seam filler.

 

[KPtexan05]

Thanks y'all! I'll try some shimming and hopefully that get's it fixed. Just wasn't sure if I needed to use some mortar or some other load bearing material to fill the rest of the gap, or if it even matters since it's just a shed.

For the door, I'd just planned on building it. It's going to be a sandwich of OSB on the backside, 2x4 frame with bracing on the inside, and the LP smart panel on the outside. That's kind of why I'm wanting the doorway to be as square as possible.

 

[KPtexan05]

"It's a shed, not a grand piano." As my dad used to say.

Haha, I really need to remind myself that. I'm sure it will turn out good enough no matter what.

 

[SweetD]

Haha, I really need to remind myself that. I'm sure it will turn out good enough no matter what.

It will! Keep posting pics as you go. A DIY shed is a great starter project.

 

[solo machinist]

It looks like your using smart board. I've used it on a few sheds and it holds up great.
I use a drip edge under the bottom edge of the sheet and caulk it, so water hangs on the metal , not the wood.
I never had a building rot.

 

[MikeC55]

If shimming against the slab, you may want to cut your own shims using PT wood so they don't rot out (too quickly). I think plastic shims are also available which might be even better.

 

[engineer2]

When I built my shed I quickly realized I was building a shed, not furniture.
A little caulk and a shim, hide the rest with sheathing and trim.

 

[slowtwitch73]

That's what trim is for.. hiding mistakes.

Fwiw I would never pour a slab for that size shed. Just put down some piers on some gravel, level it all, and have a wood floor.

 

[larry_g]

If your making the door then trim the bottom to fit the contour of the sill....

lg

 

[Moss]

It looks like you are doing a fine job, like others have said shim with your door installation and trim. As far as load bearing goes a few gaps under the sill plate that aren't bearing is totally normal you don't need to add anything but sealant if it needs it.

 

[ItsNemo]

That's what trim is for.. hiding mistakes.

Fwiw I would never pour a slab for that size shed. Just put down some piers on some gravel, level it all, and have a wood floor.

I've done it both ways, first shed was a 8x10' on deck blocks and wood framed floor, second shed was a 6x12' on a concrete pad that I bag mixed...both have their advantages but I'll take the concrete as it was easier to build on, no worries about ****/critters getting underneath, I had height constraints (was building the 6x12 underneath a deck at walkout basement level), and it's more durable/will never rot.

 

[Alchase]

I would only be concerned if water can get below the door sill and puddle inside the shed.
Otherwise, shim it and frame it

 

[ChuckkD]

Im thinking of building one similar to yours.. Whats the approx cost gonna run you when finished

 

[Ole Slewfoot]

It will be nicer square and plumb. I'd rip some full dimension shims from a PT(pressure treated) 2x....easy on a table saw, medium challenge with a skill saw cutting from both sides. Could shim up with wedges at wall and door ends, and just drive the ripped 2x4 in between them.

The other area Id look at is getting the walls to overhang the slab top in some way. Normally you'd run the siding an inch or so below the bottom of the sill plate, but metal flashing (maybe z flashing) would do fine.

 

[nadogail]

A bundle of shingles will solve all your problems regarding shims.

 

[DGersic]

I’d shim it using PT, then stuff some concrete or grout under the outside edge to finish it.

I have a PT shim under the threshold of my garage (man) door. Took a while to get it cut to fit so that the non-level concrete wouldn’t affect the pre-hung door install.

 

[theoldwizard1]

If you are going to do a double sill plate and have access to a table saw, make the second sill plate out of a non-PT 2x4 and rip it to the correct thickness.

 

[dcg9381]

I'd shim the 2x4s above the base sill plate.
Trust me 3/8 of variation is way better than most homes.

 

[KPtexan05]

Thank's again for the help everyone! I've got some composite shims I'll use to deal with this.

 

[KPtexan05]

Im thinking of building one similar to yours.. Whats the approx cost gonna run you when finished

Cost will be right at $1,700 not including taxes or slab. As far as I could tell, a Tuff Shed with similar features would cost significantly more.

Has studs 16" OC (except for that front wall), 7' tall walls, LP Smartside panel, LP Smartside trim, 25 degree roof pitch (5.6:12), 8" overhangs on all sides, radiant barrier roof decking, dimensional shingles, ridge vent, eave vents, sliding aluminum window, and transom window.

 

[ChuckkD]

Cost will be right at $1,700 not including taxes or slab. As far as I could tell, a Tuff Shed with similar features would cost significantly more.

Has studs 16" OC (except for that front wall), 7' tall walls, LP Smartside panel, LP Smartside trim, 25 degree roof pitch (5.6:12), 8" overhangs on all sides, radiant barrier roof decking, dimensional shingles, ridge vent, eave vents, sliding aluminum window, and transom window.

Thanks KP.. I appreciate it.. Thats not bad at all.. Ill build one this summer.. TY

 

[KPtexan05]

Thanks again for the help y'all. A little bit of shimming and pushing got things squared up well with the paneling and doorway!

On the subject of doors, what do you think a good amount of clearance would be to leave around all sides of the door? I was thinking 3/8" on the top and both sides and 1/2" at the bottom. The door stop molding on the inside of the frame will be made from 1x2, and I'll have a door sweep at the bottom to keep things relatively sealed.

My current progress:

 

[PelicanPines]

Great looking shed. Slabs are never level. Yours is fine... you should shim to the slab... making the plates level 360 degrees around. Your work looks great.

 

[Hank11]

Thanks again for the help y'all. A little bit of shimming and pushing got things squared up well with the paneling and doorway!

On the subject of doors, what do you think a good amount of clearance would be to leave around all sides of the door? I was thinking 3/8" on the top and both sides and 1/2" at the bottom. The door stop molding on the inside of the frame will be made from 1x2, and I'll have a door sweep at the bottom to keep things relatively sealed.

My current progress:

1/8" on top and sides, 1/4 on the bottom. No reason to leave it with big gaps. What kind of door are you planning on?

 

[Ole Slewfoot]

1/2 is too big, you get mice

 

[KPtexan05]

1/8" on top and sides, 1/4 on the bottom. No reason to leave it with big gaps. What kind of door are you planning on?

I gotcha - 1/8” sounds a little tight for a custom build shed door though? I was slightly worried about any small amount of shifting that could occur in the future. I planned on the door being a sandwich of 7/16” OSB on the back, 2x4 frame, and then LP smart side on the outside - so about 2-5/16” thick not including the trim on the outside of it.

 

[KPtexan05]

1/2 is too big, you get mice

I’ll reduce it then. I did plan on using a rubber door sweep to close that gap too.

 

[Hank11]

You are making this way too hard. Just go buy an exterior pre-hung door.

 

[rayra]

Ignorance and OCD are the Devil's playground.

Shimming the sill plates is a terrible idea in general. On a shed, who cares, but the proper solution is varying the wall stud lengths such that the top plate is level. And that's besides all the stupidity about full length shimming and grouting / sealing.
And typically the siding runs down the wall and slightly overhand the slab. And there is where your variation in slab level is hidden.

Rough door openings are typically 2" over your door size. That space taken up by the door jamb and shims - the place shims OUGHT to be.
The guy above that said 1/8" on the sides and 1/4" above doesn't know what he is talking about. OR at the very least never worked on something someone else built.

Your doorway should be fitted with a sill / threshold. A pre-hung door comes with one.

 

[PCustoms]

Ignorance and OCD are the Devil's playground.

Shimming the sill plates is a terrible idea in general. On a shed, who cares, but the proper solution is varying the wall stud lengths such that the top plate is level. And that's besides all the stupidity about full length shimming and grouting / sealing.
And typically the siding runs down the wall and slightly overhand the slab. And there is where your variation in slab level is hidden.

Rough door openings are typically 2" over your door size. That space taken up by the door jamb and shims - the place shims OUGHT to be.
The guy above that said 1/8" on the sides and 1/4" above doesn't know what he is talking about. OR at the very least never worked on something someone else built.

Your doorway should be fitted with a sill / threshold. A pre-hung door comes with one.

How do you really feel.....

This is a shed. 100 ways to do it and at the end of the day 99 will work fine

 

[CraigStu]

Rayra why is shimming the sill a bad idea? Every time I have been involved in building a wall it was built on the floor/ground/driveway and tilted up into position. Cutting every stud to a custom length would probably triple the time needed to create a wall.

 

[Hank11]

Ignorance and OCD are the Devil's playground.

Shimming the sill plates is a terrible idea in general. On a shed, who cares, but the proper solution is varying the wall stud lengths such that the top plate is level. And that's besides all the stupidity about full length shimming and grouting / sealing.
And typically the siding runs down the wall and slightly overhand the slab. And there is where your variation in slab level is hidden.

Rough door openings are typically 2" over your door size. That space taken up by the door jamb and shims - the place shims OUGHT to be.
The guy above that said 1/8" on the sides and 1/4" above doesn't know what he is talking about. OR at the very least never worked on something someone else built.

Your doorway should be fitted with a sill / threshold. A pre-hung door comes with one.

You might be talking to me, and if you are get your facts right before typing. Your post is very rude and quite arrogant. If he's making a door my call outs stand for the fit of the door in its jams. If he's buying a pre-hung it will come pretty close to the same numbers. And you sure don't want an inch each side for a rough opening. (not if you have any skill in framing and finishing) Also, he may or may not want a threshold, especially if he's rolling heavy things in and out.

 

[GirlnAgarage]

Use the sill foam under the bottom plates. Its worth 1/8" and gets you wiggle room.

 

[paredown]

The pro framer I worked with liked to set the sill plates, set the corner 2xs dead on level, then chalk line stretched tight between them if the floor was really bad. Then you would set each stud on the sill plate on its mark, hit the chalk line and custom cut. (He was also careful about crowning his wood but that's another story..) He would do this all the way through the interior walls, staircase opening etc.

This method works well because it ensures that the top plates are dead level. This becomes especially important if you are doing a second floor; otherwise the errors on the first floor get telegraphed up, and you struggle with them when you are at the top and trying to set trusses or what have you.

On a shed--close is good enough.

 

[KPtexan05]

Thanks again for the replies, everyone! I'm going with a custom built door for a couple reasons: I already have the materials and hardware, prehung exterior doors are kind of pricey, my rough opening is already sized for it, I don't want a threshold into the shed, and (most importantly) my wife wants it to match the shed with trim on the front to look like a barn door.

Work has been a bit slow since I was out of town last week, but I think I'm about ready to put roof trim/decking/drip edge on. I've never done roofing before and I'll be using dimensional shingles to match the house (HOA requirement), so I really need to do some studying about how to properly lay those. I was originally going to use 30# tar paper, but it seems synthetic underlayment is they way to go now?

Current progress: