How to build a wooden shed?

[mikebarker]

Hi all, I am about to build a small wooden garden storage shed (3m wide x 2.4m deep) on a gravel base. I have been soaking up tutorials, reading the various excellent posts on this forum and on wooden framing and feel fairly confident about most stages but there are a few grey areas that I would love the community guidance on (and will likely lean on you for tips along the way!).

I previously prepped the ground and laid a gravel pad. The plan is to put 2 x 6 treated joists directly into TuffBlocks as the base of the shed and build on top of that.

So my questions are:

Flooring

1. I am looking at treated yellow tongue STRUCAflor is this suitable or is there a better alternative? Treated plywood looks very expensive but I don't mind paying if it means increased longevity.

2. Silly question, but given the fact an exposed tongue in these boards will be at one edge of the shed. Do you just cut these off or just fill the gap with sealant?

Walls

1. What options do I have for external wooden wall panels? I would like something that looks nicer than particleboard or OSB. Is there an outdoor option of these slotted panels? I guess I could use weatherboards but curious at alternatives.

2. Should I use building wrap?

Roofing

1. What are my options here? Just colourbond sheets? If yes, should I still put a plywood/OSB roof on and apply the colourbond to that or just attach it straight to the rafters? I assume I would have lots of gaps if I attach directly to the rafters.

2. If colourbond is the way to go, I'm curious to know what you use so that you don't just have sharp raw edges and what to use for the apex of a pitched roof?

Fasteners

I'm going to use screws instead of nails for framing (Personal preference, if I had a nailgun it might be different 😄). So I don't want to have to pre-drill or anything. What gauge is best, 12g? or thicker? Something like these Buildex RapidDrive Treated Pine Screws 12g x 75mm?

I think that's all I need to know at the moment, once I have these answers I can make my materials order and get stuck in!

Thanks so much

[EricL]

Hello @mikebarker 

That is a bit of a bother having the floor out of square. Brute force tactics come to mind but I've learned my lesson as this type of repair often produces more problems than it fixes. I propose stepping back for a moment and listing the items that need to be addressed.

Will unscrewing part of the frame allow you to adjust it? Is it better to add gravel at the bottom of the plastic base rather than adding timber chocks? These are just some of the questions that you'll need to ponder on while you are trying to fix your frame.

Please keep in mind that it's better to address these issues now rather than later when it will be extremely difficult to make any changes.

If you need further assistance, please let us know.

Eric

[mikebarker]

Morning chaps,

Firstly, what tolerance for out-of-square is acceptable? If my Googling is accurate 13mm out of square is approx 0.312% of the total structure.

@Dave-1 The 4 peices 2 x 3000mm 45 x 140 and 2 x 2400mm. So it's heavy-ish but it's of course got all the joists attached now. Are you suggesting taking it apart? Also, I don't have any level ground other than the gravel base. I'm on quite a severe hill 😅

@EricL I could try unscrewing part of it, I'd really love to not take it all apart. I'll give that a go but do you not think I can square it up with the flooring?

So the chocks are a bad idea? It took so long to level it as it is but I can lift each part up and try and pack more gravel in. I'd raked and tamped the gravel so much to get to this point 😞

I agree that I need to get this part right so it doesn't cause issues down the line.

Thanks for the input

[Dave-1]

Morning @mikebarker 

Mmmmm Having a square base is definetly a priority, I would unnscew the joists and get the outside part square. Believe me when I say it will save you effort later on. Id say one ormore of the joists are too long and thats why its out.

You dont need level ground, sloped will work as well. its that suareness you need. Even if you just make the square outer edge on the gravel you have and then chocck it up to put the tuffblocks underneath afterwards would work.

Taking along time to level is part of it next time the time spent will be less and everytime you level anything you will do it faster When I did my first kitchen I had it with 3mm which was within tolerances but spent a fair chunk of time doing it before the benchtop guys came. Was worth the effort tho.

Dave

[EricL]

Hello @mikebarker 

I understand that it is a pain to do these adjustments especially when you've made so much progress. I suppose it call comes down to what you are comfortable with. If you are ok with the timber chocks, then leave them how they are. In the grand scheme of things 13mm is not going to matter a whole lot specially if no one is going to see or know about it.

However, it's important to look ahead and see if any of these things will affect the rest of your build. 

If you need further assistance, please let us know.

Eric

[mikebarker]

Morning all!

@Dave-1 So it was square before I put the joists in. Are you suggesting taking it apart and checking for square after adding each joist (Like I should have!) and adjusting as needed at those points? Adjusting I assume meaning shortening joists where needed? The joists are all the same size so perhaps there is some bowing in the outer joists.

@EricL I kinda wish I was comfortable with it being a little wonky, but I don't think I am! Just good to know what the tolerances are.

I saw people online discussing getting things square with ratchet straps, and then adding the flooring to lock it in. Also, people suggested a big hammer 😅 - I'm tempted but don't own either of those things so would have to actively choose to go down the brute force route. I think I'll go with a delicate touch... for now 😬

When I come to put the flooring on, do you think I should add some construction adhesive?

[Dave-1]

Afternoon @mikebarker 

If it was square before you put the joists in the I suspect some of the joists are different lengths and thats what is making it not square.

And yes by adjusting I do mean shortening so there is zero pressure when you place the joist inside the square frame.

It can be a pain to do, usually when I look back at a job where I am in the same position I do kick myself

Hammers work, just depends on the level and hgow you work with things that may be out a little.

Dave

[mikebarker]

Ok, we have square, and we are wood chock free 🤩

I took all the central joists out, squared it off the 4 edge joists, added more gravel to the few that were chocked, and tamped to get level. Then one by one added each joist. Checking for square and adjusting every step of the way. I didn't need to cut any joists down.

I can tell what went wrong originally: I only checked it for square before adding joists, then after, and was jostling it to be centred on the gravel base during this time. No wonder it was out.

Thanks for pushing me to do this right.

[Dave-1]

hahahah @mikebarker 

Just so you know, you arnt the only one who has done that I have as well.

Well done and now onwrads and upwards! You sound so much less stressed

Dave

[EricL]

Hi @mikebarker 

I'm glad you stuck with it. Now you'll never look back and worry that it's out of square or that it's not level. I'm keen to see the flooring installed and the wall frames assembled.

We look forward to your next update.

Eric

[mikebarker]

Yeah thanks chaps, happy to have removed that worry.

Ok on to the next concern 😅, on  I applied 2 coats of 1:1 diluted bitumen rubber paint to the underside of each flooring panel (and on the sides as best I could). It's not the thickest layer but they are covered. However today I read on the tin you should use it undiluted for a fully waterproof "membrane". I missed that part, the instructions weren't very clear. My requirement is to provide further protection from air/ground moisture so do you think what I have done will be adequate? cc/ @MitchellMc