Sub Base

[HJB]

On 11/11/2021 at 19:48, Makeitstop said:

 

Sealed...???

I think I found what he meant when he referred to sealed. This is for larger construction work form what I can read this blinding layer.

 

“In construction, blinding is a base layer of weak concrete or sand that is laid above a layer of hardcore to provide a clean, level and dry working surface. A thin layer, usually around 50 mm (2 inches) thick, of blinding is poured over the hardcore, sealing in the underlying material and leveling off the surface”,

[joe90]

I laid a patio on sand many years ago (before I came here and learnt how to do things properly!), and after a year or so the sand washed out and it all collapsed !, even my block paving I had installed on my new build was not laid on sand but on granite chips, (over type 1) builder told me they don’t wash out or sink like sand and he always does it this way now,

[HJB]

Does anyone  know if there is a governing body that you can get to check this kind of work?

 

Major concern now is that the level is not 150mm below the air vents. They have said a thin row of chips and the aqua channels means it will be ok but tbh I am at the stage now I would like someone authorised to check the work.

[joe90]

The 150mm thing is more about being below the DPC, to stop rain bounce wetting the wall above the DPC.C

[TonyT]

1 hour ago, HJB said:

Does anyone  know if there is a governing body that you can get to check this kind of work?

 

Major concern now is that the level is not 150mm below the air vents. They have said a thin row of chips and the aqua channels means it will be ok but tbh I am at the stage now I would like someone authorised to check the work.

As so then to quote the guidance where they are getting their info from, usually works in stopping people quoting rule of thumb guidance or local working practice. 
 

[HJB]

2 hours ago, joe90 said:

The 150mm thing is more about being below the DPC, to stop rain bounce wetting the wall above the DPC.C

I presumed the bottom of vents were the DPC? They are prob going to be 50mm at best below the vents 

[HJB]

1 hour ago, TonyT said:

As so then to quote the guidance where they are getting their info from, usually works in stopping people quoting rule of thumb guidance or local working practice. 
 

I suspect making it up as they go along to suit there needs to complete the job.

 

Nothing worse when things like this happen, trust in someone to deliver to your spec and within  standards set by the industry. 
 

Anyone ever had to sue a trades person before. I suspect they will have done just enough to keep they head above water. No idea how their reviews are so good.  Maybe people don’t take note during the build.

[Makeitstop]

I'd be concerned that the finished levels are going to be circa 50mm below dpc.

 

If they've had scope to prep the ground levels on this job from the off, then that to me would tell me I need to watch what they're doing.

 

I would personally be calling other pavers / landscapers to call and check what's going on, and would be more than happy to pay for their time in doing so. Of course, it needs to be someone "very" good at what they do, and not some cowboy fool that claims to know.

 

50mm below?.... Don't like it.

Edited November 15, 2021 by Makeitstop

[HJB]

It’s too far gone, only thing I can do is get someone in to check but then it’s just one word vs another not sure what I would be able to achieve.

 

I may have to ride it out until something happens like water into the vents and then I have evidence to go back to them on.

 

My other option is rip it all up in the summer and start again, losing out on thousands!

 

I don’t get why they didn’t dig it out, I pay for the digger, labour, and skips!

Edited November 15, 2021 by HJB

[saveasteading]

I think you have all the comments you need here now.

 

What I would pick from them is.

1. tell them  "I have done some homework and am concerned about the sand blinding. Show me something to confirm that your statement is correct, that this is a recommended procedure."

2. dpc, "likewise show me proof of what you think is an acceptable distance from new paving to dpc".

3. stop work and payment until you have  done this.

 

Where to find proof? Suppliers of paving products, Marshalls  being an obvious one. for block paviours they will show a sand bed, but I think it is unlikely to be appropriate for slabs.

However I can't see anything useful from them, but did find this. https://www.paving.org/index.php/how-to-lay-paving-slabs/

[HJB]

I showed them the paving suppliers guides that have no mention of the word sand, they still claim this is the proper way and and done this 1000s of time and no issues!

 

They said the DPC is not an issue as the patio stops short of the house, and water has to cross a aqua channel drain, plus a 15mm soakaway chips channel before getting to the vents.

 

I did kind of bring work to a hault, but as I stupidly paid out 50% up front to cover material and the initial labour and also I cant have the garden left as at is over winter until I  can get it sorted, plus they were starting to bang on about labour so far has been over the 50%. `I thought best to proceed, challenge this at the end and potentially withhold final payment until its checked out, although I think they may have done just enough to cover themselves.

 

I have all emails kept where he states what he is doing is correct, and that he offers a guarantee for 10 years, so if I want to stand any chance I think I have to get some flood defense items, and when the next down pour happens film it and they start the battle with him.

 

As you rightly mentioned I have enough info supplied here and thank you to all you kind people for your help, unfortunately for me the war is just beginning, and least I still have final payment to make, but not sure who I can get to back me on this, doesn't seem to be regulated. I could email my local council planning office with some photos for advice but not sure they will be overly interested.

 

Sadly I think I will have to admit defend and wait for battle to commence down the line.

 

The best bit for me is the suppliers guide to a sub base and has a photo of a guy laying the paiving on the mortar mix and guess whats under the mortar, type 1!!!!!

Edited November 15, 2021 by HJB