Timber deck over concrete verandah?

[chromis]

I've been told you can't put a timber deck over a concrete verandah.

Is this true?

[silentC]

No, it's not.

[Garves]

In a similar situation A friend of mine wants to build a timber deck over the top of a existing slab. Is there a mimimum distance between the underside of joists and the top of the slab that has to be maintaned? or can he just lay down termi-mesh and have the joists sitting on the slab. I suggested keeping a minimum distance of 30mm just for the issue of water pooling on the level concrete slab and sitting up aginst the joists. Any advice would be much appreciated.

Pete

[chromis]

No, it's not.

Information Overload

[silentC]

Oh, you wanted information too?

I did it once but it was a timber deck around a pool which had a concrete surround. I put copers around the edge of the pool and butted the decking up to them. I secured the decking to the concrete surround by dynabolting treated pine battens to it and then I screwed the decking to the battens. This was because I didn't want to increase the height too much.

If you don't have to worry about height, you can sit the joists flat on the concrete and then put decking over the top. If you have the headroom, you can put the joists onto galvanised stirrups so it's up off the concrete. I think that would be the optimum solution but it would raise the height of your verandah considerably. Another option might be to drill holes in the verandah floor and use some heavy gauge all thread and a couple of nuts to make adjustable 'stumps' for the joists to sit on.

The main concern I have with doing this is that you get crap collecting between the decking and the concrete, which could be a problem for various reasons. With mine, I started to get weeds growing in the leaf litter and other rubbish that collects down there. It was impossible to remove it because of the small gap between the decking and the concrete. If you can arrange it so that you could get a broom in there or hose it out once in awhile, it would probably be better. My kids also used to love sticking things through the gap between the decking, so keep that in mind too.

[chromis]

I think the problem would be that there's only a couple of inches from the concrete to the top of the door (4 large door/windows) step.

[silentC]

Have a good look in the renovations forums. Someone (can't remember who) did this recently and posted details, photos etc. There was a dog house incorporated into it somewhere, so that might help with a search.

[Wood Butcher]

I found the thread that silentc was mentioning except it is in woodwork pics.
http://www.woodworkforums.ubeaut.com...ad.php?t=22697
(No wonder I couldn't find the damn thread in home reno!)

[katydid]

Several things to to consider:
1. Too close to the concrete base and any water will congregate and cause rot - this can possibly be resolved if you can drill holes through the concrete slab - if this however will drain into an inapproproiate area I.E the downstairs games room ! then this is not an option.
2. Is the concrete base slanted AWAY from the house walls -i.e. to the garden? Non timber joists running away from the house (some sort of plastic strips) to raise the timber decking off the slab and drain any rain water into the supposed garden) would be required.
3. If the slab is totally falt - well sorry you're stuffed!

[ozwinner]

3. If the slab is totally falt - well sorry you're stuffed!

Not so. There is another thread going at the mo, with some usefull info on it.

Al

[chromis]

This deck from this angle http://www.woodworkforums.ubeaut.com...0&d=1129784478 looks like it had lots of height above the slab.

The slab I have is on limestone foundations. All up its about 50 cm off the ground and 10 of that is visable concrete. (anyone wanna break it up for me ) and theres only about 5cm from the concrete to the wooden step/frame of the windows and doors.

What do you do with a huge chunk of red concrete...??