Clause 804

karlitob · 24-05-2021 9:58pm #1

Typically overthinking things but is all 804 the same? I see that there is an SR1 certificate - is that something that can be verified.

Why I ask is - I’ve seen prices from €35 to €104. See below. And I think I can get a better price than the €35. Are they all the same stuff?

Thanks

https://stonedirect.ie/product/804-crushed-stone/

https://www.thegardenshop.ie/804/

Metric Tensor · 25-05-2021 12:26am

Don't order 804 online. Ring a local quarry.

You can't use 804 in or around buildings you have to use SR21 compliant material which goes through more testing and therefore costs more. (Even though it may well be the same stone!)

The grading of 804 and one of the SR21 materials (T1) is identical so you won't be able to tell them apart in your hand.

karlitob · 25-05-2021 8:06am

Metric Tensor wrote: »

Don't order 804 online. Ring a local quarry.

You can't use 804 in or around buildings you have to use SR21 compliant material which goes through more testing and therefore costs more. (Even though it may well be the same stone!)

The grading of 804 and one of the SR21 materials (T1) is identical so you won't be able to tell them apart in your hand.

Understood. Thank you. Will certainly ring a quarry.

Is it correct to say - all SR21 is 804 but not all 804 is SR21?

Can I ask what the difference is?

Another thing in life to learn about. I’m putting down a patio but it’s fairly large - 160sq m. At about 0.75sq m per tonne bag, I think I need at least 32 tonnes [ (10m x 16m x .150m)/0.75 ].

How would that sound to you?

Thanks for your reply.

Calahonda52 · 25-05-2021 8:56am

the SR 21 came from the pyrite scandal

IIRC 804 is about 1,600 kg a m3
You have 24 m3
so maybe 38 ton
you need to get it in bulk, the bag price will kill you as well as digging it out of the bags unless you get them to slice the bottom of bag while on the hook off the lorry

karlitob · 25-05-2021 9:18am

Calahonda52 wrote: »

the SR 21 came from the pyrite scandal

IIRC 804 is about 1,600 kg a m3
You have 24 m3
so maybe 38 ton
you need to get it in bulk, the bag price will kill you as well as digging it out of the bags unless you get them to slice the bottom of bag while on the hook off the lorry

Thanks for that.

What ballpark price am I looking at?

I am in the unfortunate position of having a esb wire going across my front drive.

Calahonda52 · 25-05-2021 9:48am

804 here in nenagh is 40 a bag plus delivery.I get it from Ardcroney stone and they have a little lorry that takes up to 10 ton.
I had grit delivered in a bag and it came with fork lift and he drove it down the driveway!
I could have cut the arse if needed while on the forklift
804 is v hard to get out of a bag

Metric Tensor · 25-05-2021 11:17am

karlitob wrote: »

Is it correct to say - all SR21 is 804 but not all 804 is SR21?

Not really. There's four different types of SR21 material going from large bulky filling material to fine sand for blinding.

Many people don't know that and assume the most commonly seen type of SR21 material, which is known as T1, is the only type.

karlitob wrote: »

Can I ask what the difference is?

The range of SR21 materials have gone through a series of tests, for things like pyrite, to ensure they are safe to use under and around buildings.

804 is subjected to a lesser standard of testing because it's meant for use under roads. (804 is shorthand for Clause 804 of Series 800 of the TII Specification for Roadworks)

To muddy the waters a bit: The T1 grade of SR21 material has the same size stones and passes the same size sieve as Clause 804 material. So they are indistinguishable to the naked eye.

To muddy the waters even more: There is no problem with a quarry testing their material to ensure it is SR21 compliant but also selling other materials from the same quarry such as 804, 808, 6N2, etc. etc.

I'll leave it to more experienced people than me in the area to help you with quantities - but don't forget that compacted 804 and loose 804 take up different volumes!

looksee · 25-05-2021 11:20am

Very useful information, thank you.

karlitob · 25-05-2021 11:59am

Thank you very much. Very interesting.

Point taken on compaction.

So for my patio sub base. I should go for T1 only. Would that be correct?

monseiur · 25-05-2021 12:42pm

I would suggest that the best material to use in your case is what is known colluquially as 'One inch down' It's basically one inch screenings/ Clause 804 and the mix goes from one inch to dust with plenty of dust in it, when compacted it's like concrete especially if it's limestone.

karlitob · 25-05-2021 12:48pm

monseiur wrote: »

I would suggest that the best material to use in your case is what is known colluquially as 'One inch down' It's basically one inch screenings/ Clause 804 and the mix goes from one inch to dust with plenty of dust in it, when compacted it's like concrete especially if it's limestone.

Thanks for that. Can I check is one inch down a mixture of 804 and another product that’s 1 inch?

Does 804 not contain stone up to 75mm as well dust?

Does the 804 - with its pyrite - make it unsuitable to be under a patio.

Apologies for all the questions.

Metric Tensor · 25-05-2021 12:56pm

karlitob wrote: »

So for my patio sub base. I should go for T1 only. Would that be correct?

Many might consider that overkill for the entire patio. You only HAVE to use SR21 material for filling right up against the building*. The rest does not have to be SR21 compliant. Having said that - for a small job it might be a bit ridiculous to order two different types of materials.

(*Opinions differ on how much but standard practice is to use SR21 compliant material under the footpath around a building - so the first 1m or so. A strict reading of the standards might allow you to reduce that a bit but you're getting overly picky then!)

Obviously there would be nothing wrong with using SR21 compliant material throughout provided the grading of the material suits you needs.

Metric Tensor · 25-05-2021 12:57pm

karlitob wrote: »

Does the 804 - with its pyrite - make it unsuitable to be under a patio.

The VAST VAST majority of 804 will have absolutely no pyrite in it. It just isn't tested to the same standards to prove that.

karlitob · 25-05-2021 1:12pm

Metric Tensor wrote: »

The VAST VAST majority of 804 will have absolutely no pyrite in it. It just isn't tested to the same standards to prove that.

Understood.

Then for a patio - there really little benefit in going for T1 over 804.

I presume when you say ‘whatever grading you need’ you mean T1. I know there’s different types.

Is there a major cost difference between both?

hesker · 25-05-2021 2:44pm

monseiur wrote: »

I would suggest that the best material to use in your case is what is known colluquially as 'One inch down' It's basically one inch screenings/ Clause 804 and the mix goes from one inch to dust with plenty of dust in it, when compacted it's like concrete especially if it's limestone.

This is good advice.

If you’re not going for SR21 then this is the stuff you should use.

804 can often have very little fines it in. It will not compact well with a small plate compactor. You need a good mix of fines as well as larger stones to get good interlocking and a nice level finish.

One inch down means largest is 1 inch (in one dimension I think) and then all the way down to dust.

karlitob · 25-05-2021 3:24pm

hesker wrote: »

This is good advice.

If you’re not going for SR21 then this is the stuff you should use.

804 can often have very little fines it in. It will not compact well with a small plate compactor. You need a good mix of fines as well as larger stones to get good interlocking and a nice level finish.

One inch down means largest is 1 inch (in one dimension I think) and then all the way down to dust.

Thank you.

I have to say this is all very confusing. I thought I read that 804 has lots of dust in it.

I need 38 tonnes - and without too simple - what do I ask the man on the phone for?

hesker · 25-05-2021 3:32pm

karlitob wrote: »

Thank you.

I have to say this is all very confusing. I thought I read that 804 has lots of dust in it.

I need 38 tonnes - and without too simple - what do I ask the man on the phone for?

I’d recommend you go to the quarry and have a look for yourself and even have a chat with them.

The first time I did what you did. Picked up the phone and ordered a lorry load of 804. I asked was there plenty of fines in it and he said there was. The reality was a little different though as I found out 3 days after the truck had driven away.

You can buy more fine material and mix it in if that happens but would be better to avoid that hassle.

Metric Tensor · 25-05-2021 3:55pm

karlitob wrote: »

I presume when you say ‘whatever grading you need’ you mean T1. I know there’s different types.

The posts that follow mine explain why I said "whatever grading you need." There's no guarantee that a material that is designed for a sub-base underneath macadam layers on a public road is the correct material for underneath patio slabs. But you'll get as many opinions on what to use as there are different patio slabs and patio installers.

To add to the complexity all of the published "grades" have a range that's acceptable. So 804 from quarry A will be close to 804 from quarry B but not necessarily identical. This is the allowable grading chart for 804:

https://imgur.com/a/K1tNbsk

You can see from the chart that material can have anywhere between 10% and 35% by mass of its content below 1mm in diameter and still be 804 provided it meets the rest of the range.

johayes999 · 07-11-2022 2:08pm

What is the difference between clause 804 and 3/4" down? Using for underlayer of driveway, gravel going in top.

Clause 804

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