Posted: Wed Jun 21, 2017 10:37 am
We recently had a patio completed, 30sqm. The slabs are 20-30mm, quite heavily rivened slate for what it's worth. Ranging across 3-4 sizes.
The Builders were brilliant with it, and when realising how poor the sub surface was ended up going as deep as 300mm in some places - 200mm throughout otherwise. This was all whacker plated down in layers, followed by a solid 40mm mortar bed which the slabs were laid on. I watched them do a good chunk of it so know the quality of the foundations.
Edging was done to a high standard and then we agreed to joint it with a Nexus Projoint V75 commercial grade/7.5tonne rated 2 part epoxy Resin - just because I like to 'over engineer' wherever I can.
All was well and true, until I walked across it in socks. Turns out one of the largest slabs - 900mm x 600mm has a hollow knocking noise from underneath an edge of it, there is also a very fine hairline crack between jointing compound & the slab edge approx 400mm long where this hollow noise is.
This knocking noise is only from approx 15% of the slab, the other 85% seems solid. There is no noticeable movement in the slab itself (that I can see or feel), just this knocking noise & hairline crack between it & jointing.
I have tried to pin down the builders over the last couple of weeks, but through the grape vine heard they went on holiday & have two full extensions on their books at the moment. I therefore have had no luck in getting them to discuss this with me - a real shame seeing how friendly & hard working they were.
Now I am torn between up the antee & either getting someone else to pop the slab up and relay it on a slurry (or try it myself without cracking the slab) and spending £60 for the jointing compound vs leaving it as is, trying to seal this hairline crack and see how it goes.
Any advice? I am particularly anal when it comes to things like this, so may be drastically over thinking it - i admit. Just looking for peace of mind from better educated folk?
Many thanks in advance
The Builders were brilliant with it, and when realising how poor the sub surface was ended up going as deep as 300mm in some places - 200mm throughout otherwise. This was all whacker plated down in layers, followed by a solid 40mm mortar bed which the slabs were laid on. I watched them do a good chunk of it so know the quality of the foundations.
Edging was done to a high standard and then we agreed to joint it with a Nexus Projoint V75 commercial grade/7.5tonne rated 2 part epoxy Resin - just because I like to 'over engineer' wherever I can.
All was well and true, until I walked across it in socks. Turns out one of the largest slabs - 900mm x 600mm has a hollow knocking noise from underneath an edge of it, there is also a very fine hairline crack between jointing compound & the slab edge approx 400mm long where this hollow noise is.
This knocking noise is only from approx 15% of the slab, the other 85% seems solid. There is no noticeable movement in the slab itself (that I can see or feel), just this knocking noise & hairline crack between it & jointing.
I have tried to pin down the builders over the last couple of weeks, but through the grape vine heard they went on holiday & have two full extensions on their books at the moment. I therefore have had no luck in getting them to discuss this with me - a real shame seeing how friendly & hard working they were.
Now I am torn between up the antee & either getting someone else to pop the slab up and relay it on a slurry (or try it myself without cracking the slab) and spending £60 for the jointing compound vs leaving it as is, trying to seal this hairline crack and see how it goes.
Any advice? I am particularly anal when it comes to things like this, so may be drastically over thinking it - i admit. Just looking for peace of mind from better educated folk?
Many thanks in advance