Hi all. My patio is pretty uneven. I think the guy who laid the slabs the last time did a pretty bad job (ok, it was me). The slabs are a little riven, so don't have a perfectly flat underside. I laid these on top of the original patio base which I think is ok. I recall just putting some big blobs of cement under each one.
How should I redo them?
For full disclosure, I'm very happily married, so don't need to hide anything underneath (but she's called Louise, so maybe she's playing the long game?
Assuming they will lift okay, just lift, remove old dabs and relay them.
If it was me I'd also point them up to stop the weeds growing through.
Ta. Will certainly point them
Schoolboy error, should have chopped the bodies into smaller bits.
(When I say 'relay them' obviously I mean relay them with new dabs and put plenty on. However you *may* end up with the same issue. Unfortunately I think it would be very difficult to do a proper job without lifting the whole lot and laying a proper solid base.
I've got similar and they're a pain in the arse, pretty much impossible to get them completely flat, but use a plank of wood to span others with a spirit level on top to get them level ish....
Use a bit more mortar than you think as it'll all spread out beneath the slabs and give a better bed.
This site is full of very useful information
https://www.pavingexpert.com/layflag3
Remember bedding mix uses sharp/concreting/grit sand not building sand.
For pointing, have a look at the brush in epoxy type, e.g. Rompox
For full disclosure, I’m very happily married
You are either married or happy you can't chose both..... blink twice if you need help
We had a patio the same as that laid on sand. Apparently that's the way to do it now!
As expexted, it's rubbish. Lots of moving slabs.
Apparently that’s the way to do it now!
Pretty sure it isn't
Not sure what your slabs are made of but I laid a porcelain slab patio last summer.
I had a compacted 100mm of aggregate (100mm after compacting) as my main base - spent ages with one of those petrol compacting tools - quite fun actually.
Then I laid a wet mix mortar under the whole slab using a slurry on the back of the slab to make sure it stuck to the mortar (porcelain isn’t porous so it needs the extra slurry).
If your slabs are porous then if you have a decent hardpack layer of something under them I’d do a full wet bed rather than just dot and dab I think.
Full bed is better IMO. Less to move and cause unevenness. Basically spread down a full bed of mortar, then plough grooves into it to allow it settle nicely. Tap the slab in to level it and it should stay there. You do need to get the amount of mortar right as it won't settle that much but after a few slabs you'll have the measure of it. Using the old base should be fine as it'll be well compacted.
We had a patio the same as that laid on sand. Apparently that’s the way to do it now
Its really not the way to do it for that kind of patio, especially if its riven. Sand is for brick patterns or huge slabs like proper council paving.
I'm not arguing, I agree it's not the right way. But several sites advise doing it.
https://www.marshalls.co.uk/gardens-and-driveways/blog/how-do-i-lay-a-patio-on-sand
As the the guy that laid it.
I'm debating (after failing to get him to resolve) pulling up and doing it properly.
https://www.pavingexpert.com/layflag3#bound-or-unbound
An unbound base can be fine if you know what you're doing. However the slabs need to be the same thickness (i.e. calibrated) because you have to fully compact/consolidate the base. You can't do this for riven flags
Lots of useful info. Thanks. I did wonder about a full bed. Will read up on it.
Having had trouble laying sandstone in the past, and then getting a professional in I followed their tips for another section I did later and after a couple of years all is well.
Firstly lay on a full bed not dabs. The paving expert website will also advise this.
Assuming the slabs lift up clean then apply a brush of SBR & water slurry to the back of the slab to help adhesion with the mortar.
Finally a little building sand mixed with the sharp sand also help with bonding.
I used a proprietary ready mixed pointing compound which is easy and clean to lay but is fairly pricey and I’ve found it needs patch repairs after each winter. All in all I’d prefer this than the potential mess of wet pointing for the narrow joints.
Firstly lay on a full bed not dabs. The paving expert website will also advise this.
It does. However it doesn't advise this..
a little building sand mixed with the sharp sand also help with bonding.
The reasoning being that building sand will weaken the bedding mix and there are other ways of increasing the bond strength.
