Advice on small patio

[Jlwater]

Hi

 

I’ve filled an old pond that the previous owners had on the garden. The plan is to lay patio to the same level as the existing patio, but I’m not sure on a couple of things. 
 

I want to patio up to the fence but wonder how to border the two. The fence is raised a bit above where the patio will be, so need to make sure the mud underneath doesn’t eventually collapse in or anything. 
 

im also not sure how to make sure I get the exact same level as the existing patio. The pond area is currently about 10 inches below the top of the existing patio, so I’m thinking it’s ready for the sub base and patio, but how do I ensure the patio sits flush with the existing? What material is best for the sub base?

 

Any advice is appreciated. I’m hoping to keep this a DIY job, with the possibility of getting a professional in to do the whole lot in a few years. 
 

thanks

josh

[alfaTom]

Think about the fact you've taken a pond out and added sub-base in.

If the fence stayed where it was when a pond was present then it should stay where it in once you have the sub-base in.

You're not leaving it hollow so it'll have something against it.

 

For sub-base I would use MOT1, Wacker plate it and sand blind. Might be a bit OTT but I think you'll need to compress it well into the old pond space to stop it sinking.

 

As for ensuring it sits flush...you measure it and level it. Get the depth of your new patio slabs and subtract that from the build up, allowing for a cement mix underneath. I'd do full cement on the slabs, none of this 4 dots in the corner like some companies will do.

[Jlwater]

Thanks mate. 
 

Previously the pond wasn’t flush with the fence, there was a bit of soil between some railway sleepers (the pond border) and the fence. I want to make it look half decent, but I also want to make sure I don’t shoot myself in the foot if we end up getting a new fence in the future!  

 

I’ll take your advice on the sub base Material and cementing the slabs, much appreciated. 

[Jlwater]

2 hours ago, alfaTom said:

Think about the fact you've taken a pond out and added sub-base in.

If the fence stayed where it was when a pond was present then it should stay where it in once you have the sub-base in.

You're not leaving it hollow so it'll have something against it.

 

For sub-base I would use MOT1, Wacker plate it and sand blind. Might be a bit OTT but I think you'll need to compress it well into the old pond space to stop it sinking.

 

As for ensuring it sits flush...you measure it and level it. Get the depth of your new patio slabs and subtract that from the build up, allowing for a cement mix underneath. I'd do full cement on the slabs, none of this 4 dots in the corner like some companies will do.

Can you have too much sub base material? I’ve seen online to have about 100mm, but I’ll Be needing quite a bit more because the hole is deeper and I haven’t got anything else to fill it with. Would be an extra 50-100mm or maybe even more. Cheers

[Conor]

3 minutes ago, Jlwater said:

Can you have too much sub base material? I’ve seen online to have about 100mm, but I’ll Be needing quite a bit more because the hole is deeper and I haven’t got anything else to fill it with. Would be an extra 50-100mm or maybe even more. Cheers

No, you just nee d to ensure you compact it in max 100mm layers. Hire a 12" whacker from the likes of Speedy or HSS for a weekend. I think the key here is making sure everything, including the pond in-fill, is really well compacted. How are the existing slabs laid? Directly on to sand? Best to match that method with the new bit. And make sure you figure out the fall on the existing section and match it with the new one, you dont want water ponding between the two areas.

Edited July 18, 2023 by Conor

[Jlwater]

23 hours ago, Conor said:

No, you just nee d to ensure you compact it in max 100mm layers. Hire a 12" whacker from the likes of Speedy or HSS for a weekend. I think the key here is making sure everything, including the pond in-fill, is really well compacted. How are the existing slabs laid? Directly on to sand? Best to match that method with the new bit. And make sure you figure out the fall on the existing section and match it with the new one, you dont want water ponding between the two areas.

Thanks and will definitely get a whacker plate on hire, been compacting as I go but manually rather than with a motorised one. Knackering! 
 

as for the existing slabs, my worry is these have not been done properly anyway. They seem to be laid on top of the original concrete without much consideration for sloping away from the house. So it’s quite built up around the house and closer to the damp proof membrane than I’d ideally like. There is a decent gap between the brick and slabs though. In an ideal world I’d get the whole lot re done properly but I think it would just be too expensive. I’m not sure whether to level the new patio with the existing, or a bit lower and eventually get the whole lot done properly.
 

thanks for the advice