Limestone or Granite as a primary aggregate

[Thorfun]

Hi all. I'm looking to get some MOT Type 3 for my driveway sub-base. it seems that some places offer Limestone and some Granite as the primary aggregate.

 

simple question, is there any difference in performance or cost between the two?

[PeterW]

Limestone can go claggy in rain then rock hard when it dries which causes run off issues. Granite doesn’t bind as tight so is more free draining. 

[markc]

Granite is free draining while limestone holds water. The load bearing capacities are not important with a driveway. 

Granite should be more expensive but they may have railway ballast available.

[Thorfun]

Just now, PeterW said:

Limestone can go claggy in rain then rock hard when it dries which causes run off issues. Granite doesn’t bind as tight so is more free draining. 

thank you! so, if purchasing for a permeable SUDS compliant sub-base it would seem that granite is the better option. ? 

[Thorfun]

1 minute ago, markc said:

Granite should be more expensive but they may have railway ballast available.

that's interesting. the company that has granite type 3 does have railway ballast on their website. I think I'll give them a call and ask if I can put that down with type 3 on top to reduce costs (assuming the railway ballast is cheaper than the type 3 that is!)

[PeterW]

Some BCOs will not allow you to use railway ballast as it’s a waste product and can be contaminated.  

[Thorfun]

13 minutes ago, PeterW said:

Some BCOs will not allow you to use railway ballast as it’s a waste product and can be contaminated.  

ok, they didn't have any anyway. I think I'll stick with Type 3 all the way down. might be a bit more expensive but reduces complexity and risk.

[Phaedrus]

41 minutes ago, markc said:

The load bearing capacities are not important with a driveway. 

 

My understanding is that both hydraulic and structural considerations are important for a SUDS compliant driveway.  What full make up do you see as being acceptable?

[nod]

3 hours ago, Thorfun said:

Hi all. I'm looking to get some MOT Type 3 for my driveway sub-base. it seems that some places offer Limestone and some Granite as the primary aggregate.

 

simple question, is there any difference in performance or cost between the two?

Reclaimed will give you the best of both and also cost less 

[joe90]

3 hours ago, PeterW said:

Some BCOs will not allow you to use railway ballast as it’s a waste product and can be contaminated.  

They will only notice if they sniff it ?

[Thorfun]

1 hour ago, nod said:

Reclaimed will give you the best of both and also cost less 

can't find any at the moment down this way. tried lots of companies and no one seems to have recycled type 3. which is a shame.