Other Any builders here? Need deck advice

RIP Claude Hammer though - a brave soul he was!

How did you get rid of the weird fuzzy stuff? It looks like it might have been dangerous! Since revealing it, have you developed any special powers?

 

I put on a mask and gloves, then brushed it all up into the bin.
No super powers though

 

Boo - I wondered if you might have inhaled some strange spores from the fuzz and developed an exciting superpower!

/threadderail

(sorry OP)

 

So here's my plans (click to enlarge):



The side which is 7200 is the house facing wall, I had planned to anchor the deck to this wall and have the four circles as support posts.

For the side of the deck so we think this is going to be enough to support it ok?

 

My deck is about 5m wide by 3m deep and I have 15 posts supporting it! (3 rows of 5).

 

This is where I'm not 100% on stuff as I don't know if I need that kind of amount or if that's overkill or what to think

I was hoping that attaching to the wall of the house would reduce the need for as many posts so maybe I got the wrong impression.

Is there a rule of thumb which says for every x m/sq I should have x amounts of posts to support it?

 

To be honest, you don't need too many posts, the important thing is where they're placed and how you line up the bearers on top of them.

Personally I would add maybe three more posts, positioned in the middle of the ones you have already and the house. That would allow you to have three bearer beams running from left to right (including the one attached to the house). That would be much stronger than the arrangement you have now, not much more complex to do either. Basically run the bearers left to right on top of the posts and then place the boards at 90 degrees to those on top. It would mean that the boards are well supported from underneath, which is important if they're to last and remain safe.

EDIT: About to set off home, could draw a diagram when I get back if you like? Unless somebody beats me to it that is.

 

Please that would be great, I think I understand where your going with it but pictures say it all

 

First question should have been what's it going on,IE, mud ,grass, concrete, old slabs, swamp? Then how high is it off the ground. That will play a factor in how it goes together.

Are you going to put it on posts with purlins then joist across the top, similar to how Yodas looks?

If you're going straight across you might need to think about how you are going the joists

 

Couple of points,

Why are the posts 1/4 in?

This could have the potential to create a pivot point and place undue stress on the fixings to the house. plus you could also experience some bounce towards the outer edge.

Number of posts corresponds to the span of the beams, if a beam can only span 1m then you need a post every meter. TRADA span tables should give you some good info on this.

Could do with some more info on height and the direction you want the decking to go.

 

My initial thought is...



But don't hold me to it.

 

The height of the deck will be about 200mm at the house and around 300mm at the furthest away.

Decking spans are looking to be from left to right parallel with the house laid in a 2x 3600 lengths, followed by a 1800, 3600 & 1800 then continued on to the end (imagine brickwork type pattern).

Archtronics - where you say the slab of the beams, do you mean the length of the beams running 90 degrees from the house?

Asura- the extra 4 post you've drawn on, is that based on leaving the posts where I suggested or would I be better moving them back towards the mid point to even out the spacing?

 

I think the total number of posts and there span would depend entirely on how big your posts are and how thick the timber you use to build your framework is. Just bear in mind that your large deck may have 10 people and furniture on it. That will mean it needs to support about 1000Kg plus the weight of the timber itself.

I don't like the idea of using the wall of the house as a structural support as you'll need so very strong fixings to hold that weight on sideways, at least with the posts the framework can be on top of them so that weight is holding them in place not being held by horizontal bolts.

 

Yeah I see what you mean. Maybe I'll just have to accept there maybe more digging involved then I wanted lol.

Framework will be 150x50mm treated timber and the post will be 100x100 to a depth of around 450mm.

I had planned on attaching to the house with M12 anchor bolts or epoxy anchors but this was based more on what I'd seen on several online videos etc rather then any real work experience or advise.

 

The thing is the post holes don't need to be that big so the digging is pretty limited, if you use postcrete and a hose pipe it'll take you less than 10 mins to do each post.

Also don't forget to treat the cut sides of your posts before you bury them, I used I roller tray full of creosote substitute and just sat the cut sides in it for a minute or so to let them soak it up a bit.

 

Astonished you made it look like that, after seeing the "before" picture.

 

Yes sorry Span=Lenth.

Essentially what I'm saying is the number of posts relates to the strength of your beams. If you have a beam that can take a load over 2.2m then you would only need to surpport it at either end.

An example of a beam span table for domestic floors.


I will do you a quick paint image when I get home of what I would do.

 

Please that would be great. Unfortunately I don't know a lot about the beams she's got planned as she went to a local timber yard with her dad but lost the sheet with the quotes on. I'm pretty sure it was down as 150x50mm and tanalised.

 

Couple more questions... I can see it's 7200 long, but how wide is it coming out?

And if possible have you got a pic of where its going to be put.

 

Instead of.

The wall will take the load just fine; M12 anchor bolts just like you said, one every 400/600 staggering their height on the beam. Probably need a 16mm hammer drill bit, and if you can borrow a SDS+ drill it'll go quick as a blink - I wouldn't buy one just for this job though, a bit over the top for normal DIY. If not, drill a pilot hole with a 6 or 8mm bit prior to the sixteen it'll speed up the process, in fact - drill the pilot regardless.

If you prefer to have the posts set back from the edge then that is an option. You'll need to move your beams back to sit over the posts. Your joists then over-shoot the beams, and the decking on top of that. It's a cantilever, but not a big one so you probably wouldn't even need to go thicker.

Think Primary structure, Secondary structure, Finish. The primary is a frame of posts resting on beams, the secondary is a grid of joists which sits on top of this, and the finish is the decking timbers, each is stacked on top of each other like jenga, rather than all on a level. They can go all on a level if you want; that involves buying joist hangers, screwing these to your beams, and your joists into the hangers. However, it's more metal exposed to the elements, so unless you need to minimize the height...