The Brew Cabin

Posted: **Mon Apr 09, 2018 10:02 pm**

Hello

I want to build a block patio in my back garden (only for my family walking, not vehicles)
Instead of a MOT1 subbase, I'm thinking about using CONCRETE FLAG PAVING 600 X 600 X 50MM, that I can find for about 7Â£ each.
These tiles are wide and heavy and have a load capacity over 3.2MPa.

Reasons I thought about flag paving as subbase:
- there are already some big and thick concrete flags next to the wall that I'd like to leave (they are not going to come up anyway, the alternative would be breaking with a heavy duty hammer drill)
- I'm not very experienced and I think levelling will be easier
- There is a rusty manhole that I cannot open and I'd like to just put these big concrete flag paving on top

On top of the concrete flag paving (50mm high) I'm planning on putting sand 30mm and than the patio blocks 200x100x50mm

Before I start doing this, I'd like to hear your opinion. Please let me know if you think it's a bad idea or it's fine

Regards, Mauro

Posted: **Mon Apr 09, 2018 10:11 pm**

Very bad idea. Just rip them up and do the job right. Also a complete no no to cover manhole cover. Think you need to grab a six pack and sit down to read the index.

Posted: **Mon Apr 09, 2018 11:12 pm**

Sean is correct
never cover an inspection cover,otherwise what happens when your drains block?
also no matter how big and heavy these slabs are they are virtually useless as subbase
you could rip them up break them into small pieces and reuse as long as they are compacted
you must be careful to keep the finished height 150mm below DPC
cheers LLL

Posted: **Tue Apr 10, 2018 9:01 am**

To lay the flag paving correctly, you'd need to excavate, lay a sub-base of granular aggregate, then a bedding layer to support the flag.

In your plan, your then envisage puting a second bedding layer over the flags, and finally the pavers.

This is a very bad idea.

Not only are you replicating work, and making it a far bigger and costlier job than it need be, it's a bad construction as you have large pieces that could potentially shift and/or settle buried beneath smaller pieces. If your plan was to omit the sub-base layer completely and lay flags directly on the sub-grade (earth) then it's a disaster waiting to happen.

Omit the flags - even at 7 quid apiece, it's cheaper to use a proper sub-base - and do the job properly.

Posted: **Tue Apr 10, 2018 7:56 pm**

Thank you! I will buy a sub base then

The Brew Cabin

Flag paving as sub base?