digging out rock

ISAA

All,

I got planning permission in the last few weeks, and we have a lot of rock to digg out,

1) any idea of pricing a) per hour or the job
2) foundations at the same time.

regards,

onq

ISAA wrote: »

All,

I got planning permission in the last few weeks, and we have a lot of rock to digg out,

1) any idea of pricing a) per hour or the job
2) foundations at the same time.

regards,

PRICING:

If you want pricing information you have to estimate:

1. The quantity of rock to be removed
2. The difficulty of access & transport
3. The difficulty of removal

All affect the final price.

What can throw you is an inadequate estimate of the difficulty or removal which in some cases may require unusual methods:

a) blasting
b) compressed air techniques
c) specialist heavy duty machinery

In addition the degree of difficulty can be affected by restrictive working hours in your permission or excessive noise not anticipated by adjoining propertyholders which results in an injunction.

At a minimum you need a competent civil engineer to advise you in relation to site investigations and boreholes to assess the issues involved and advise a Quantity Surveyor on difficulty and methods of removal to establish a price.

Or you could try asking your local JCB driver if he's done any rock removal in the area and ask him for a fixed price.

FOUNDATIONS:

Well, you could get some use out of your engineer and ask him to design both the foundations and the groundwater drainage system because the level of rock suggests there may be difficulty with water moving through the soil.

DRAINAGE:

You could your ask you engineer to advise on your intended soak-away and comment on your drainage system outfall, because a reduced amount of topsoil and rocky substrate may affect both of these matters negatively.

You should perform Trial Holes tests and percolation tests to the latest applicable standard if you have not already done so.

ONQ.

gman2k

There is also chemical rockbreaking, which may be more suitable if you are building in a built up area.
Basically, a circa 50mm hole is drilled into the rock,
Chemical substance poured into hole (usually a form of quick setting cement)
This expands rapidly and cracks the surrounding rock,
Which can then be picked clear with a rock picker.
Advantages are less noise, and minimal vibrations to nearby buildings.
some planning conditions stipulate the use of chemical rock breaking in urban areas.
But as ONQ says, you need an engineer to advise.

DOCARCH

Have used chemical rock breaking on granite. It's very effective.

Poor Uncle Tom

You really need to know what you're dealing with, and it's way too vague to deal with accurately here without a hell of a lot more detail.

onq

Gman2K and DBK100,

Thanks for the advice about the chemical method, which seems to follow the requirement for drilling needed for the compressed air system.
Neither may prove to be useful if the rock in question is too hard as we discovered on a site several years ago.

The granite was so hard that it was blunting the pike attachment on the JCBs - weathered granite top layers quickly gave way to living rock beneath with no fissures, faults or seams - wasn't doing the JCB any good either...

The contractor had never seen rock like it - an entire day just to chip off a piece about 300mm long - its possible a diamond drill and either the chemical or compressed air method might have worked, but it looked doubtful so we eventually got in a heavy duty rock breaker from England which performed the task.

As Tom says "You really need to know what you're dealing with..."

ONQ.

Poor Uncle Tom

onq wrote: »

....and DBK100,.

Just curious as to why the above reference since that poster has not posted since 15th January and not on this thread.

ISAA

Why not uncle tom ? as I said just got approval, and looking for good advice, and here is excellent.

regards,

onq

Poor Uncle Tom wrote: »

Just curious as to why the above reference since that poster has not posted since 15th January and not on this thread.

I toggled two open windows and didn't twig the dates on them or the forum ID's.

All these forums look the same y'know - well, two do.



ONQ.

Poor Uncle Tom

ISAA wrote: »

Why not uncle tom ? as I said just got approval, and looking for good advice, and here is excellent.

regards,

Well for instance you haven't told us if the site is level or sloping at say, 1:5, the depth you need to dig out will to an extent determine the machinery you use, or whether your site would be terraced, etc.
We don't know what type of rock you have on your site, whether it is soft, hard, in layers, veins, sheets or slabs, if it has a 'grain' and whether that is angled, horizontal or vertical, does your site rock also contain you watertable? Can the rock be reused on site, can it be used as facing stone, will it need to be transported off the site, etc., etc.

ISAA

Uncle Tom,
since you seem to know what you are taking about, and I don't, would you be interested in checking out the site ? and giving me a price ?

Regards,

onq

ISAA wrote: »

Uncle Tom,
since you seem to know what you are taking about, and I don't, would you be interested in checking out the site ? and giving me a price ?

Regards,

Repetition for effect.

"At a minimum you need a competent civil engineer to advise you in relation to site investigations and boreholes to assess the issues involved and advise a Quantity Surveyor on difficulty and methods of removal to establish a price."

ONQ.

Poor Uncle Tom

ISAA wrote: »

Uncle Tom,
since you seem to know what you are taking about, and I don't, would you be interested in checking out the site ? and giving me a price ?

Regards,

Thank you, no. But, what area of the country are you in, I know some very experienced people who would go on-site, asses the situation, and give you costings, I could PM some details if I knew the area.