New patio -conflicting advice - Laying over existing cement and patio

[RobH]

Hello all.

I was hoping to grab some sound advice on a new patio that I am having laid. So far I've had 2 contractors out but I've had conflicting advice. The patio is at the rear of my house and all materials would need to come through the house and down one level using the balcony stairs.

The patio itself is about 40m2 with with some steps at the rear to a lower lawn area. Currently this 40m2 area is on two levels one being about 8 lower than the other. The higher section is a cement screed which is in two sections divided by a piece of wood (almost rotted away) but one part is not in great condition and I feel it has sunk a little over the years. The lower section has 600x600 concrete flags about 2 inches thick. It looks like these flags are just laid on earth.

The builders that came out offered 2 different approaches. The first wanted to remove the old flags and backfill with sub base to increase the level to height of the cement section. He was then going to lay directly over the cement screed.

The second was going to leave the flags and backfill on top about 6 inches and then lay over the cement screed. this option would mean that no materials would have to be taken back up and out of the house. It sounds great but I'm not sure how this would fair in a few years and I'm concerned that it may shift and crack.

I'll post some pictures soon as I can. Ideally it would be great to use the cement and old flags in some way. If the builders suggestions are not sound would it be ok to break up cement and or flags and use them in the lower area to increase the height?

Really appreciate your help.

Thanks

Rob

[lana]

Rob,
while waiting for the professionals to speak, take a look
here. Laying on top of the old surface better to be avoided, if possible. I also would assume it is perfectly fine to re-use crushed old material in sub-base, I had it done this way when building my terrace. Saves on materials.
Lana

[RobH]

Thanks Iana, yes did see that but it implies it could be done in certain circumstances. Laying on old flags especially mine is a no no I guess but I'm not sure if it would be ok if 6-8 inches of sub base is on top of them.

[RobH]

I should also say the the height is not an issue for the DPC. thanks

[DNgroundworks]

Hard to say really, but 6/8 inch of mot on top of the flags doesnt sound too bad an idea to be honest, especially with the access situation at your house. Id be tempted (in fear of getting flamed) to put a sledge hammer through the flags, literally leave them where they are and put the mot on top?

The integrity of the flags would need checking on site first of course.

Are the flags sound? or are they rocking etc?

[RobH]

Hi DNgroundWorks. Yes thats what I was hoping, break the lot up and use it as a base for the lower level. The flags aren't rocking, they've been down for 20+ years but as said are just on earth. I was thinking to smash up the cement and flags and use it for the base that was there would be less backfill needed to bring up the lower level. Just wondered if this was an acceptable compromise given the costs to remove everything from site ( and mess through the house).
Appreciate input, cheers.

[seanandruby]

Sounds like you could do with some temporary stair protecters. i have about 30 + used ones.