Type 1 question

[Sammy]

I hope someone can help me....

I had a estimate for a new block paved driveway. The contractor has told me they will dig down 8 inches. This will be made up of 4 inches of crushed concrete, 2 inches of sand and the final 2 inches being the block paving. After reading through these forums 4 inches or 100mm of sub base seems to be the minimum required and 6 inches is preferrable. The ground below is clay. Would you advise that I ask him to dig down an additional 2 inches? I've also seen on these forums that Type 1 is a better product than crushed concrete. After checking a few websites though there seems to be 2 types of Type 1, limestone or crushed concrete. Should I be asking for Type 1 limestone option?

Thanks

[Tony McC]

Type 1 is a grading specification. It can be used to grade limestone, crushed concrete, granite, diorite, sandstone or other suitable aggregates. The key thing is that, if it's Type 1 compliant, then it's good enough for your driveway regardless of whether it's crushed concrete or anything else.

There are crushed concretes that are NOT Type 1 compliant, and these are best avoided, but if, as I said, the crushed material being offered is demonstrably Type 1 compliant (ie: the contractor can produce a grading certificate to that effect), then there's not a problem.

As for whether you should have 100mm or 150mm, that depends on how firm is the sub-grade. If it's firm, reliable clay, then 100mm might be OK, but if there's any doubt, then 150mm would be the better option.

Over and above all of this, however, I would strongly recommend you get at least two more quotes. Relying on just one price is NEVER a good idea.

[Sammy]

Thanks for the quick reply. I've had 3 quotes and this one came in the middle. He'd completed a driveway in a nearby road recently which looks excellent now (of course only time will tell) so I knocked on the door and they put me in touch with him.

I'll take your advice though and ask him to go down another 2 inches which will give me peace of mind. Thanks for clearing up the Type 1 issue. As I have a choice of getting the T1 limestone or T1 crushed concrete would you recommend one over the other? The crushed concrete is certainly cheaper.

Thanks again

[lutonlagerlout]

did he include terram or multitrack for underneath the type 1??
this definitely helps
regards LLL

[Tony McC]

Crushed concrete is more environmentally friendly, by about 3 microns, and as long as it *is* Type 1, it's fine for driveways.

[Sammy]

Thanks for pointing me in the right direction. I'll leave the choice up to the contractor then but insist on type 1. None of the 3 quotes included terram or multitrack. What are they and are they necessary?

Cheers