tips needed for new gravel driveway

[scummings]

Can anyone give me some tips on a new gravel driveway. The excavation is done, it's nice and level and once we have our log home delivered we will put in culverts and drainage ditches. We were told by the excavators that it would be a good idea to first put down a "filter fabric" available locally for about $1.00 a foot at 12' width, then put our gravel down to prevent the gravel from sinking.

If we put down the fabric, do we have to put down the big gravel or can we go with a smaller gravel? Is there a more economical alternative? The driveway is at least 600' and will be a mudhole if we don't do something to prevent the gravel from sinking.

Is the price good or can it be bought cheaper elsewhere? I'v searched the internet and found articles on geotextile fabrics, but no pricing, is this the same stuff? It's all so confusing with all the different types, can someone enlighten me please?

Also, how is it put down?

Thanks,
Sheri in KY

 

[bridgeboy]

Do you trust the contractor? Sounds to me he's telling you the truth.

You don't get good work for free.

 

[KRSServices]

I agree with bridgeboy, it appears as though the contractor is giving you a reasonable approach. When applications of geofabric and additional reinforcement are required, it becomes costly. One alternative may be to look at constructing a different structure (ie. pit run and crush) and comapre the costs. You may be able to strip off the unsuitable and replace with a layer of pit run, then a thinner layer of road crush. As long as you don't overload it and aggregate is not too expensive, it may be a cheaper way to go, considering that we are only referring to a driveway in this instance and not a road.

Best of Luck! KRS Services

http://www.krs-services.com

 

[scummings]

I never meant to imply that I didn't trust the excavators, they did a fantastic job on the driveway and excavation for the basement and footer. I know it's going to be expensive, we are looking at over $1500 just for the gravel and the fabric. I was just wondering about alternatives if there were some and trying to get an understanding of what the fabric was. I'd rather spend the extra in the beginning than have a mud pit for a driveway.

 

[cvg]

$1.00 for 12 square feet is a reasonable (cheap) price. It may cost more than this. Note: this is not the stuff you get at Home Depot. I usually use about $2.00 per square yard (installed). This includes allowance for overlap and waste. Make sure they overlap the edges and ends of the rolls. You may want to ask for the specs on this material. Make sure you get the right material for the job. You could probably get a specification from your county road department or from the state highway department.

Minimum recommended :
grab elongation - 45% - 115%
grab tensile strength - greater than 400 N
puncture strength - greater than 135 N
burst strength - greater than 900 kPa
trapezoidal tear strength - greater than 135 N
apparent opening size - 106 - 600 micrometers
permitivity - 0.07 sec -1
UV stability - 70%

these are all tested and should be certified using ASTM test methods

this would be the cheapest, lowest quality - recommend you could go higher than this and get better results...

 

[NZSteve]

Sheri
The vast majority of roads in New Zealand are constructed of a granular type material similar to what you're constucting.
The main reason that you put filter fabric down is due to a concern that fines (mud and silts) will slowly move up from the insitu (existing) materials and into you pavement. this action is similar to when you slurp up water from, say a spill on you carpet with a thick sponge.
As you contractor has said filter fabric and not Geotectile fabric you would assume that the insitu material is reasonably strong but just has a problem with this fines migrating.
If CVG is correct you're looking at 600' x 12' x $2 /9 = $1600 for the fabric (sorry haven't used feet and yards in ages)
A bit of cost i would think. As this problem only exists when you have water close to or in the granluar layers a simple solution that might remove the requirment for fabric would be to construct your culverts and ditches immediately, then allow for a small reshape of the material when all your construction trucks have finished running on it.

 

[KRSServices]

Y'know, now that I have had more time to think about your query, relative to costs and practicality, I do not think that putting down the geo-cloth, all issues being considered, under gravel is such a good idea. I've built countless miles of "rural" cross section of road, with varying soil types. Provided that the driveway is sufficiently drained, you do not need to put down the cloth, it will be a waste of time and money. If you are trying to contain the gravel in a wet area, such as constructing the driveway in a muskeg or swamp, then that is different. If the driveway as it exists now is wet surficially focus on constructing properly.

Strip off the unsuitable material (organic).
Blade the drainage ditchs and utilize the excavated material for your grade.
Compact the material and grade.
Place a uniform layer of traffic crush.

Over time, the gravels will be absorbed into the subgrade as it were, but morre than likely they will be bladed into the ditch (if you have snow).

Add more gravel as necessary over time. If you have a cloth, the light layer of gravel will not compact properly and you will lose it into the ditch anyway. If the suggestion is a thick layer of gravel on top of the cloth, then "borrow" some fill from an excavation or import some pit run and then place your gravel. You can email me if you wish further info. Bottom line, I think it to be a waste of money for the cloth....and I build roads for a living.
KRS Services

http://www.krs-services.com

 

[dec4trax]

You will have to determine how well drained and how compact your base soils are.

If your soils are sandy, you probably dont need the fabric.

If they are fine grained (clay or residual soils) and have been suitably compacted by the road grading contractor and use of the driveway by daily access, using a geo-fabric for separation will keep your gravel layer cleaner and free-draining for a much longer period of time. If you do not use the geo-fabric, the gravel surface will lilely perform the same, but the subgrade will pump and choke the gravel surface with fines much more quickly. You will probably want to add a gravel overlay in a few years as the roadway gets used and the wheel ruts start to form. The Fabric will probably double the life of your gravel surface (3 year overlay, as compared to a 5-6 year overlay - assuming car and light truck use).

If your soils are fine grained, but the subgrade is soft or weak, I would not use the fabric immediately, but rather plan on periodiccally placing layers of crusher-run materials when necessary, as the gravel materials settle into the subgrade from the downforce of the tires. Eventually, the crusher run stone will have combined with the soft soils and bridge the softer soils below, and you will have a fairly firm road surface. At that time, I would place the geo-fabric and a layer well graded gravel.

What it realy comes down to is what type of surface you are willing to live with, and how often you are willing to do maintenance and add more gravel overlays. The geo-fabric will extend the maintenance cycle.

What I would also suggest, is that you dont initiate final gravel placement on the driveway until the contractors and delivery trucks finished building your home. Install your your storm drainage and culverts, and place a minimal layers as necessary to provide traction. Over time, you will soon identify identfy where your soft areas are or where additional drainage is need drainage. After the home is complete, then concentrate on fixing the soft areas and placing the final gravel surface. I am a civil engineer, and a strong proponet of using geofabrics when the soil conditions warrant use of a separation material or filter.