Garden decking

Postby markwilliams82 » Tue Aug 18, 2009 8:32 pm

I'm looking into putting some decking in my garden. I've never done any decking before so am looking for all the help I can get.

the area where I want the decking is concreted over however the ground isnt level, and one end is higher by about a foot compared to the other side.
can i put decking on to this? or how can i go about getting it built?

any help would be appreciated
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Simply Build It

Postby aeyres » Wed Aug 19, 2009 5:00 pm

Without knowing where the deck is in relation to your house, & the concrete quality, i will assume away from the house (as vertical walls can be used to fix to) & good quality concrete slab.

Essentially, what you need to do is make your sub deck perimeter frame timber to the size & shape you require without fixing it to anything. Place it in position (over your concrete) & using timber or plastic packers, level the sub frame out to the desired height (remember you will want a slight fall for the water to run off)
Depending on your frame timber size, Counter bore 25m holes around your deck frame (arrrox 1/3rd down) then drill remainder with 10mm hole to enable you to directly bolt fix through the timber & into the concrete. Use M10 x 150 Concrete fixings or anchor bolts. The concrete will need to be marked & drilled with (8mm masonry if using threaded concrete bolts) or 10mm masonry for anchor bolts. Remember to re-check everything is still to your desired level. Fix the frame securely bolting through timber into concrete at regular positions (ensure your fixing positions are adequately packed out)

Where you say there is a foot difference, this is slightly more tricky, as you will probably need vertical posts fixed to the deck frame. Here you will have to use some steel 'L' brackets at the foot of the posts to fix into the concrete. Standard nut, bolt & washer through the timber & concrete fix the base of the 'L' brackets to the floor as above.

Hope this gives you some ideas.
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Postby markwilliams82 » Wed Aug 19, 2009 8:45 pm

That was a brilliant and really helpful reply thanks! You've really given me some ideas and shed some light on some things.

Especially when you mentioned about the location. Its hard to describe, but some of the decking will actually be against a wall. I've tried to do a picture

So from what you're saying I could secure one side of the frame to the brick wall, and having it slope off slightly towards the garden/lawn for water run off. The corner on the left between the fence and the wall is where the floor is at its highest so mounting on the wall would make things alot easier as a guide for a good level which would provide a level floor to the decking. the side on the right will be near soil so I should be able to get some post supports there and upright posts to mount the frame on if I'm right?

How does that sound? And hope the "rough" picture helps to illustrate what I mean

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Postby aeyres » Thu Aug 20, 2009 9:13 am

Couldn't view your picture, but yes, use your wall to fix the frame to & this will give you an ideal starting point. If you are putting vertical posts into the soil, dig at least a foot down, might be an idea to use Postcrete to cement them in place, or break up some paving slabs to give the post a solid base, then backfill your soil ensuring it is well compressed.

Hope this helps.
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Postby markwilliams82 » Thu Aug 20, 2009 9:26 am

Not sure why you cant see the picture, think you just need to put the link into your browser instead ... 116lo.jpg#

I'll only be able to put the one side of the frame against the wall, but like you say it'll provide a perfect starting point, and will give me the positions needed for securing the posts in the soil.

Is there any rules on the layout of the frame inside the outer 4 frames? of can they just run parallel to the outer frame work?
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Postby aeyres » Tue Aug 25, 2009 7:44 am

Joists are usually spaced 400-500mm apart...might be worth also checking the DIY doctor website for decking projects, as it will probably give you better diagrams etc. on most of the things you will need to do. Post positions etc
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Postby markwilliams82 » Sun Aug 30, 2009 7:39 pm

Got all the wood for the frame today so weather permitting I plan on making the frame tomorrow and getting it set up, and then over the course of the week fix the decking top.

one question though is should the frame sit on top of the posts into the ground or will screwing the frame onto the side of the posts be sufficient?
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Postby AlGBarker » Tue Sep 08, 2009 11:55 pm

Hi Mark,

I'm building decking in my garden at the moment too (hope the weather has been better for you as it has been for me!)

I found the following site had some quite useful tips:

I noticed that you are planning to attach one side of your outer frame (ledger board) to a wall. Just remember to leave a gap between the ledger board and the brick work to allow for drainage. Between 1" - 2" spacers should be enough.

With regards to your posts, either way is fine though I personally prefer coach bolts + washers to screws. If you put the frame on top of the posts then just check to make sure it sits over the centre... you don't want the whole decking to slip off the edge mid BBQ.

I'm not sure about the size of your decking, but mine is 4.75m wide across the back of the house with the joist running parallel to the house. I've had to put in 4 support joists under the frame in the opposite direction as each joist needs to be supported every 1m - 1.2m or so

Step 2 of the link above should be helpful.

In general the more the supports the better as this will increase strength and help stop the deck from having too much of a spring. I've put my support joists 1m apart.

Good luck and keep your fingers cross for some sunshine.

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Postby markwilliams82 » Wed Sep 09, 2009 7:40 am

That's a great website! Thanks!

I got all the framework built the weekend before last when the weather was dry...luckily and I'm having the decking boards delivered on Friday to finish the job off if the weather stays dry! Although I'm so determined to get it finished this weekend I'd probably get soaked :lol:

Thanks for your help Alan

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Postby 1truescott » Fri Apr 09, 2010 11:55 am

remember that if you are attaching your decking to your house, that some areas will require planning permission, as the attachement will consititue an extension of the footprint of your house!

Check with your local planning office to cover yourself!

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Postby TheDoctor4 » Tue Jun 29, 2010 7:23 pm

If you would like to find a reliable, insured and vetted tradesman in your area why not click through to the Find a Tradesman area of DIY Doctor: , complete the form and receive up to 5 FREE quotes
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