concrete pillars for deck + other questions

26 Jan 2012
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United Kingdom

I am planning on building a deck with pergola over the top coming out from my patio doors at the back of my house and wondered if anyone could offer some advice and answer some questions I have.

The garden currently looks like pic 1 below and I would like to build the deck from the end of the wall on the left hand side to just past the patio doors. The area will be 4.8m wide and come out from the house 3m.

What I am aiming for is like pic 2 below

The questions I have are as follows....

1. I was planning on concreting 100x100 fence posts for deck supports and also legs for pergola into the ground however I have been reading that is is not a good idea since the posts will rot in concrete. I read that it is better to use concrete pillars in the ground and then use bolt down anchors to attach deck supports and pergola legs to the concrete pillars. Something similar to the pic below. Is this advisable ?

2. If I went with the concrete pillars and the posts attached the top would it be advisable to do this for the pergola legs and also use these legs as supports for the deck ? So basically use the pergola legs as part of the frame for the deck. Or should I build the deck and then attach the pergola legs to the top of the deck using the bolt down anchors like in the picture below

3. I would be building the deck over the below access points for drains so had thought I could have a section of deck which can be lifted (like a trap door) to give access to these drain points - is this advisable or am I just asking for trouble building a deck over these

4. My plan is to raise the deck to the height of the patio doors. As you can see from the picture below there is a raised step area roughly at that height. Do I need to completely remove this step area or could I lay deck boards directly over the top of the step area which is at the same height at the patio doors. There will be a pergola with roof over the top so not too much rain so fall on the actual deck but I was bit concerned that the deck boards that were sitting on the paving stones could be sitting in water and rot

5. if the width of the deck/pergola is going to be 4.8m wide and 3m out from the house how many upright support legs for the pergola would be required across the front - would 3 legs be adequate

I've got some other questions but will leave it there just now and hopefully someone can offer some advice on all or some of the questions above.

many thanks

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assuming scottish law is the same you need planning permission for a raised platform [decking or other] above 300mm
thanks for reply big-all.

When i first thought about doing this project last year I enquired about planning permission and was told as long as the height of deck doesnt exceed 600mm and the height of pergola does exceed 600cm and also the roof doesnt join the house roof no planning permission was required.

The height the deck will be raised is only 300mm anyway so I think I should hopefully be fine

assuming scottish law is the same you need planning permission for a raised platform [decking or other] above 300mm
as way of update the planning permission has changed and the deck mustn't be above 50cm from the ground and the overall height of pergola musn't exceed 2.5m from the ground.

might have to rethink a few things ....

If anyone could offer any advice on any of the questions i raisedi would be very grateful plus if anyone knows where I could buy any post base feet (similiar to the below) to fit a 6x6 post again I would be very grateful as the only ones I can find are for 75x75mm or 100x100mm[/url][url][/url]
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For decking support post if you use timber you should make sure that they are UC4 treated. This is better than normal Tanalised treatment as it has a water repellent in it as well.
You can also buy incised posts that have small indentations before treating this makes the treatment go in further.
The Canadians use a system of small concrete pads for each pillar as you have suggested to raise the post out of the ground, have a look for the TV show Decked Out for some great ideas. Also searching Q-deck will give you some great guides on what to use for each component and how.

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