defects liability + poorly installed granite paving

slipstream

* mods: also posted in gardening as touches on both areas *

Hiya,

We got 80sqm of yellow granite paving installed as part of an architect led major house renovation a year ago.

Looking at it now, there are a few problems as per the attached -
1) some slabs are loose, have moved or have hairline cracks
2) a bunch of slabs edging the garden have fallen ~ 5mm toward the garden
3) looking closely at the slabs; many are touching and have begun to chip at those locations
4) after rain, rather than drying evenly there are 4-5 moist patches on many of the slabs that dry out more slowly

When we started noticing these problems I read more about paving here and it seems likely that many of our issues are probably down to -
a) butt jointed slabs with no pointing resulting in movement and chipping
b) using spots of mortar rather than a full mortar bed

Now our builder is returning soon for final snags and will be looking for his 5% defects liability retention.

At installation time, we never discussed the bedding and jointing of the paving.

Are spot mortar beds and butt joints with no pointing standard practice with granite slabs in Ireland?

Given that we did not specify exactly how the granite paving should be installed, could any of this fall under the defects liability?

Thanks for your help,

Slip

Metric Tensor

Just point out the defect and say it needs to be fixed - see what way the builder proposes to fix it. Don't get into the specification with him - that's the Architects job.

I feel obliged to point out that if that's the worst defect you have the job must be a very good one!

Calahonda52

I don't know under what liability clause it falls but it is a crap job, period.
The main reason for no grout in the joints is that granite stains very easily so it takes care and attention to get it done properly so the builder thought he would hoodwink you.

They need to be relaid.
ps had to smile at this in the link
You don't need a degree in engineering to see that this type of construction offers buggerall in the way of support for flagstones

slipstream

Metric Tensor wrote: »

I feel obliged to point out that if that's the worst defect you have the job must be a very good one!

yes, in general we are happy with the build and think we were lucky with the builder we got.

there are lots of smallish issues like -
1) paint appears to be coming off several fibre-cement ridge tiles
2) lots of plaster cracks and nail pops
3) movement in architraves resulting in several internal doors which rub or no longer close properly

i ask about the paving because i'm worried he will do whatever he can to avoid pulling them all up and reinstalling with a full mortar bed and joints/pointing etc.

sconhome

Paving is supposed to be a flexible surface and I still can't understand the reasoning behind laying paving on either mortar or full bed cement. Paving of any kind should be laid on compacted sand screeded to allow falls to drainage. When the ground shifts or settles the paving can be easily lifted and repositioned.

If anything you could have them laid in a dry sand bed with cement 'stirred' through to add some reinforcement without permanent bonding.

Granite in my opinion should be grouted not with sand & cement but with a compound like Rompox which fills the fine joints and provides a seal to the porous granite surface reducing future staining and algae growth.

The chipping comes from the installation where the granite is chipping each slab as it is laid. A compound grout would minimise the look of that.

slipstream

Do you guys think it would be possible to pull up and relay the granite slabs on a full sand/cement bed or would they be unusable?

What size joints should 600 x 600 granite slabs have and would your typical builder be able to do this properly?

Would a jointing compound like rompox add a lot of expense over 80sqm?

sconhome

slipstream wrote: »

Do you guys think it would be possible to pull up and relay the granite slabs on a full sand/cement bed or would they be unusable?

What size joints should 600 x 600 granite slabs have and would your typical builder be able to do this properly?

Would a jointing compound like rompox add a lot of expense over 80sqm?

TBH a lot depends on the specification from the architect in the first place as to how they were to be laid.

Yes they can be lifted and relaid, I definitely would not be going full mortar bed. Dry sand cement blend is workable and stabilises the bed enough.

The joints are usually tight like that for cut granite slabs. 2-3mm tile spacers are handy way to set them right. Granite looks horrible with big joints.

I can't remember what the cost of it is but well worth it in the long run, preventing staining of the stone and being a proper jointing compound.

slipstream

sconhome wrote: »

TBH a lot depends on the specification from the architect in the first place as to how they were to be laid.

the architect did not specify the paving in detail. he just indicated the type, amount and provided plans of the layout required.

sconhome wrote: »

Yes they can be lifted and relaid, I definitely would not be going full mortar bed. Dry sand cement blend is workable and stabilises the bed enough.

The joints are usually tight like that for cut granite slabs. 2-3mm tile spacers are handy way to set them right. Granite looks horrible with big joints.

I can't remember what the cost of it is but well worth it in the long run, preventing staining of the stone and being a proper jointing compound.

what jointing material would you recommend for the narrow joints?

a couple of other things i noticed -
1) i thought some slabs had dropped toward the garden but in fact many of the slabs adjoining the house have dropped inward toward it.
2) some of the slab joints with the house are large (> 10mm). sand was used to fill these but much of this has been washed/blown away and in other locations it is permanently wet. what should be used in large joints like this?

thanks sconhome