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Roots lifting patio
petermcparland84
Posts: 4
We had a new patio laid last Autumn and about 3 months ago we noticed the patio slabs lifting , it has gradually got worse so we got the builder back and he said they were being raised by a strange type of matted looking weed forcing their way up .
any advice as to what it could be would be very welcome .
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It's hard to get an ID from the pics as they're too small to zoom in to get enough detail.
An inital guess would be Field horsetails (Equisetum arvense) if they're a thick mat. Lifting slabs though must be a very serious infestation if these are the culprit.
Thanks Dave ,here is another picture showing more detail if it helps , the slabs were only lifted by the builder today , the roots further down are dark in appearance .
Yep, that looks like horsetail to me. I'm planning to re-lay slabs over these guys after having some building work done.
The old slabs we took up were ex-council so very thick but when I lifted them what I found was a deep brown matting of roots that to be honest only showed that the plant had looked for the edge of the paving stone as a way out so it worries me that no matter how wide I make the patio - this beast will find the edge and come up!
Were your slabs cheap? (no offence intended, just trying to plan my attack!).
Had a look a some pictures of field horsetail and yes they are the same as what I have , the slabs I had laid were Indian sandstone , they are not as thick as I would have liked but look great , I am now thinking dig out best I can and then ask builder to do a thicker layer of concrete before re laying slabs .
When you say dig out best you can ... these plants are legendary for how deep their roots go - apparently gardeners who were also coal miners in the NE recognised their roots way, way down deep.
It's also rumoured that they were around when the dinosaurs walked the earth.
They also have a waxy coating making them impenetrable to normal weed sprays.
My approach so far has been to spray them with almost neat SBK - they go black and die off but there is no reassurance that this is death down to the roots (so far anyway, I'm still fighting the battle).
I'm thinking that I might need a good solid layer of concrete to suppress it and a barrier going deeper at the edge of the patio to contain it.
But then it has spread next door .... duh duh duh (dramatic effect!)
Ok thanks to all who replied to my question, much appreciated
My concern would be more about the quality of the preparation and the sub-base used by the people who laid the patio. I wouldn't expect a patio which was laid under a year ago to be lifting irrespective of what lays beneath.
Very infornative posts Cloggie!
Agreed with KT53. The slabs wouldn't be lifting now if the job was done properly... but it's a tricky situation.
I have building work going on right now with foundations and slabs of poured concrete going in for a garage and a utility room where our old garage was (some of it was wasteland - the house was a do-er upper). Part of that old area was riddled with this plant.
I am now seeing it popping up through concretey bits at the edge of the building works. I'm spraying these sprouts with SBK but it is still going to be a fight I can see.
I would say that if the contractors didn't know that this problem existed then they wouldn't have put in extra measures to combat it.
If they did, and they were legit, then they would have charged a lot for the job and wouldn't have been surprised by what's happening now.
Did anyone know about this weed when the job was priced? <cringing> because I don't think so.
As has been noted this stuff grows through anything including. I'm not sure the builder can be held to account to be honest. Yes, a concrete sub-base mat have delayed the problem but it wouldn't have stopped it ultimately coming through.