Patio over concrete - Complete novice, help needed

[rosemary44]

Hello, and thanks for all the useful info on this site.

To explain our patio situation: at the moment we have a large, purpose-built, shed at the bottom of our garden (approx 14ft wide by 7ft deep). It's built on a concrete floor which is bounded by a breeze block wall on the right, a brick wall at the rear, and a wooden fence on the left, although there are a few layers of bricks at the bottom on the left too (which go above the level of the concrete). The concrete appears to have lots of small stones in it, and I haven't seen any cracks, although I haven't yet looked very carefully.

What we'd ideally like to do is knock the shed down and make a patio straight over the concrete, either brick or small tiles like setts (I think that's what I mean). Then we're going to put up a pre-fab shed of half the size (7ft by 7ft) and have a dining area on the other half.

We have no experience of building patios, although are reasonably practical and won't start work until we have a clear plan of how things will proceed. What I really need is some advice on whether our idea is practical, and how best to achieve good drainage. I've had quite a good look at this site, which is great, but I'm still a bit unclear about the best drainage strategy for us. Should we use just sand over the concrete, or this 10:1 mix? Can we level the sand at an angle, and will that help with drainage? Should we put some kind of gutter in and would that involve drilling into the concrete (in which case, how would we do that?).

Also, any opinions on how long you think the whole job might take us would be helpful (min two people working, hopefully three).

Thanks ever so much.

[Rich H]

Do you have a photo, Rosemary?

The short answer is that it sounds pretty straightforward and is not (on the face of it!) a difficult job. A picture or three would help to see the lie of the land and these walls a bit more clearly.

[rosemary44]

Cheers Rich, I'll take some photos this evening and try to upload them.

[rosemary44]

Hello again. I've taken some photos but have realised they're a bit big and also I haven't uploaded photos to the web before so it may take me a bit of time tomorrow to work out where to put them.

[Rich H]

Use flickr or some other. They give you size options if you then want to post on a forum.

[rosemary44]

Just checking that this works. Hopefully this should be a picture of the existing shed:

http://www.flickr.com/photos/27183505@N08/2533533410/in/photostream/

I'll put up the links to the others in a bit. I think they have too many pixels for this site...

Rosie

[rosemary44]

I'm not 100% sure but you might be able to see all the photos from that link. I took ones of down the left and right hand sides of the shed, and down the back, although access is a bit difficult, plus some close ups of the concrete. You can see a large green patch inside the shed where the water pools when it rains. I also took one of the front edge of the concrete, I'm not quite sure what the best option for edging the front will be. Obviously we're also aware that the patio will be quite a bit higher than the garden, but that seems fine.

Rosie

[matt h]

your base is quite small and there is little drainage provided by the fall of the concrete. the little stones are the ballast in the concrete and add strength to the mix. the green patch is algae and you ought to clean it off before proceeding with th patio build. have a look at the main site as your finish can be achieved in a variety of ways:)

[rosemary44]

Thanks matt. I'm not quite sure what you mean by the base being small though?

Having looked at this website, here is my plan for building a patio:
1) Site preparation. Knock down shed... Clean concrete thoroughly - is there anything particularly good to use for this or just water and elbow grease?
2) Edge the front of the concrete. Haven't quite decided what kind of blocks would be best. Bed the kerb blocks in concrete. Do we then have to wait for this to dry before the next stage?
3) Lay a 1:10 mix over the site, which should now be bounded on all sides by bricks/blocks. Compact the sand. If we level the sand at a gradient will this aid drainage?
4) Lay setts/cobbles (or possibly bricks).
5) Fill in the gaps, the setts you get which are joined together with thin plastic cords seem to have quite wide gaps between them, can they be filled with dry sand or do they need proper pointing?

Presumably it's good if this goes from start to finish in dry weather?

Is there anything further we can do about drainage? You're right, the concrete won't drain very well as there are dips in the surface.

Cheers,

Rosie

[matt h]

cleaning use geosel eco chem
let your bedding blocks dry
levelling at gradient will assist drainage
advise properpointing mortar between flags
yes good weathr is a bonus
and if you are laying on a weak mix you can get rid of dips . best of luck. post photies!:D

[rosemary44]

Hi there, well stage one is complete. We've got the old shed down (there are some pictures of it being deconstructed on the link below - it looks like a neater job than it was!). Anyway, we'd be really grateful if people could check that out plan for what to do next is alright:

Stage 2 (hopefully this w/e, fingers crossed for the weather)
1) clean the concrete base with geocell eco chem - can we then do step 2) almost immediately?
2) there's some pictures of the blocks we're planning to use on the flickr site below. The concrete base is bounded on the left and right sides and at the back, but not at the front, so we were going to put a line of the angle-topped blocks at the front. Apparently you can buy ready mix concrete for this? We're getting our stuff from Ridgeons if anyone can recommend products. We're a bit confused about how to get a neat edge for the front of the patio, as looking at the edge courses page of this site it looks like we're supposed to have a big front of concrete. So we can't just lay the blocks completely on top of concrete then, there's got to be some on one side of them? Also we have no idea how you put concrete down best, does it need something to hold it in place while it's drying?
3) we're also planning to lay a soldier edge round the whole thing, should we bed this in concrete too and do it at the same time as 2)?

Stage 3 (maybe next w/e) Do you think two inexperienced people can do all the laying (basically 4-6) in a (long!) day?
4) lay a 10:1 mix of sand and concrete (again, you can get these ready mixed maybe?) and level it (with a slight gradient from back to front) using tips from the screeding page.
5) do a 45 degree herringbone pattern, starting at the back, laying the whole blocks first and then cutting the edge pieces and putting them in at the end. We're not sure whether we should lay the whole thing out before we lay the sand, and cut the edge blocks at this point, or if we should lay most of the blocks properly on sand and then cut the edge ones when we know exactly the space they need to fill?
6) pointing! Not sure about this yet, but basically do we use a compacter to go over the whole thing, which should throw up some of the sand, and then brush more between all the cracks?

Thanks v much for reading!! All advice gratefully accepted.

Pictures are here: http://www.flickr.com/photos/27183505@N08/

R

[matt h]

lay most of blocks and cut in situ pointing depends on the finish you want