Posted: Sun Jan 18, 2015 6:33 pm
Hi Folks,
This question relates to a few categories but I'll post here to start. I'm a competent DIYer but haven't done anything like this before except for a loose paved shed base so apologies for stupid questions and wrong terminology!
The problem: My patio is to the rear of the house 13x3m. The house is on a downward slope so the patio is raised on a bank then has steps from the centre going down to the lawn. It is currently paved with horrible 20x20cm pebble dash effect slabs. The base (or lack of it) is concrete at the steps and a couple of the corners which are sound. The rest of the base is just rubble and earth so predictably it has sunk in places and is generally very uneven and rain pools in the low spots. The slabs on the earth are not mortared in any way. It's original to the house (40 years) so the uneven base is now very compacted and firm.
Plan A: Initially I thought of building shuttering around it, levelling with suitable aggregate, compacting and then filling with concrete (100mm deep) reinforced with steel mesh (possibly overkill but I don't want it to break up). This would then be a good firm base to lay exterior tiles on. Tiles would be easier to cut / lay especially on the steps.
Question 1: Is a slab of this size possible without breaking up due to expansion & contraction? If not I assume I need control joints every 3ish meters which is going to look really ugly due to the close tile spacing. I'm confused here because I've seen larger concrete slabs with no control joints that don't seem to have any cracks but everywhere I've read has said they are necessary.
Plan B: Level, aggregate & compact and then use mortar and chunky flagstones. The steps could be tiled in a different material which is not ideal.
Question 2: If a concrete slab of this size expands and contracts, why wouldn't the mortar? I assume it does but because the gaps between the stones are chunky it is less noticeable and would only need re pointing after the initial cracks?
In a nutshell, I need a solution that is not going to break up, is hard wearing but is also fairly easy to fit. Would either of the above work or is there another way of doing it?
Any suggestions appreciated.
Thanks,
Alex.
This question relates to a few categories but I'll post here to start. I'm a competent DIYer but haven't done anything like this before except for a loose paved shed base so apologies for stupid questions and wrong terminology!
The problem: My patio is to the rear of the house 13x3m. The house is on a downward slope so the patio is raised on a bank then has steps from the centre going down to the lawn. It is currently paved with horrible 20x20cm pebble dash effect slabs. The base (or lack of it) is concrete at the steps and a couple of the corners which are sound. The rest of the base is just rubble and earth so predictably it has sunk in places and is generally very uneven and rain pools in the low spots. The slabs on the earth are not mortared in any way. It's original to the house (40 years) so the uneven base is now very compacted and firm.
Plan A: Initially I thought of building shuttering around it, levelling with suitable aggregate, compacting and then filling with concrete (100mm deep) reinforced with steel mesh (possibly overkill but I don't want it to break up). This would then be a good firm base to lay exterior tiles on. Tiles would be easier to cut / lay especially on the steps.
Question 1: Is a slab of this size possible without breaking up due to expansion & contraction? If not I assume I need control joints every 3ish meters which is going to look really ugly due to the close tile spacing. I'm confused here because I've seen larger concrete slabs with no control joints that don't seem to have any cracks but everywhere I've read has said they are necessary.
Plan B: Level, aggregate & compact and then use mortar and chunky flagstones. The steps could be tiled in a different material which is not ideal.
Question 2: If a concrete slab of this size expands and contracts, why wouldn't the mortar? I assume it does but because the gaps between the stones are chunky it is less noticeable and would only need re pointing after the initial cracks?
In a nutshell, I need a solution that is not going to break up, is hard wearing but is also fairly easy to fit. Would either of the above work or is there another way of doing it?
Any suggestions appreciated.
Thanks,
Alex.