Recommendations to shoot / determine a grade on proposed road

[beowulf]

We will be building a second house on our property (90 acres -foothills). The selected site is on a hill much higher than where any access road would begin. County Fire requires that new driveways have no more than a 12% grade (with turnout, etc.) but will permit up to 20% in some situations - and may want any steeper grade paved. A rough guess of the length of the new driveway/access road is 150 feet. I will know more about that distance and the top and bottom elevations tomorrow.

We will be hiring a contractor to build the road and to prepare the pad (will round off and drop the peak about 6-8 feet). We are not ready to build yet as need to finalize things with contractor and County takes a long time so we are maybe 4-6 months out. The grading contractor prefers to wait until we have had some rain as everything is now really bone dry.

There is another 'sort-of' road to the hill top but it's about 3 to 4 times as long as the new proposed route, has a few curves, and ends up on the wrong side of the proposed home. It would be more costly to maintain, would be much harder to use by concrete and lumber trucks, and is less private than the new driveway would be (in case we ever divide the property).

Anyway, I guess that is a lot more information than is needed for my question, which is: The best way to roughly calculate grades we can achieve, etc. If it is not reasonably possible to make the grade work out along the route of a new drive we will focus on the existing road - widening etc. I have a tripod and laser level but it is sort of useless in daylight (cheap one). We want to plan a bit while we are waiting - and will enjoy the challenge of it all as we are always restless here - and it would also be useful to know early on the best route, what trees may need to go, etc..

My thinking is that with a smart phone we can know the elevation at given points and thus determine the 'total' rise in elevation we need to make, and then can measure the distance along different route options to determine - roughly - the grades at different points. The new driveway should be a fairly straight shot.

So, is there any thing anyone can recommend to make this easier and/or any devices to help us out that won't be crazy expensive? I know the contractor can shoot this much easier, but again, we would like to have a bit more knowledge than we now have. As always, thank for any help with this.

 

[bcp]

I use a phone app named "Theodolite" that is very useful for angles and grades.

Bruce

 

[dodge man]

I am a recently retired land surveyor and the weak part of cheap hand held gps is the elevations. If the area is wide open, no trees you might get decent results but I would not count on it.

They make cheap hand held levels, like a small telescope, about 10” long. Usually no magnification. I would put lath in every so often, say 25 feet measured in, and start at the bottom and work your way up the hill. You will need to know how high your eye is and make a mark on the lath ahead of you with a helper and measure how high the mark is.

For example, your eye is exactly 6 feet high, you make a mark on the lath 25 feet away 1 foot above the ground. That means the ground is 5 feet higher in 25 feet which equals a 20% grade. Keep in mind you can not measure higher than you stand, so if the ground in 25 feet is 7 feet higher you will have to set lath shorter than 25 feet. Keep in mind it shoots level, not up or down hill. This method is not great but is very cheap. They also make hand levels that will shoot up hill and show a grade on a scale on the side but are hard to find these days.

Some counties and states have free topo maps available. You probably need a way to print them out to scale them though. The quality of there software varies also on if you can just get the measurements on your computer or need to print it out.

Of course a surveying or engineering company could survey and design something but not cheap.

 

[fried1765]

We will be building a second house on our property (90 acres -foothills). The selected site is on a hill much higher than where any access road would begin. County Fire requires that new driveways have no more than a 12% grade (with turnout, etc.) but will permit up to 20% in some situations - and may want any steeper grade paved. A rough guess of the length of the new driveway/access road is 150 feet. I will know more about that distance and the top and bottom elevations tomorrow.

We will be hiring a contractor to build the road and to prepare the pad (will round off and drop the peak about 6-8 feet). We are not ready to build yet as need to finalize things with contractor and County takes a long time so we are maybe 4-6 months out. The grading contractor prefers to wait until we have had some rain as everything is now really bone dry.

There is another 'sort-of' road to the hill top but it's about 3 to 4 times as long as the new proposed route, has a few curves, and ends up on the wrong side of the proposed home. It would be more costly to maintain, would be much harder to use by concrete and lumber trucks, and is less private than the new driveway would be (in case we ever divide the property).

Anyway, I guess that is a lot more information than is needed for my question, which is: The best way to roughly calculate grades we can achieve, etc. If it is not reasonably possible to make the grade work out along the route of a new drive we will focus on the existing road - widening etc. I have a tripod and laser level but it is sort of useless in daylight (cheap one). We want to plan a bit while we are waiting - and will enjoy the challenge of it all as we are always restless here - and it would also be useful to know early on the best route, what trees may need to go, etc..

My thinking is that with a smart phone we can know the elevation at given points and thus determine the 'total' rise in elevation we need to make, and then can measure the distance along different route options to determine - roughly - the grades at different points. The new driveway should be a fairly straight shot.

So, is there any thing anyone can recommend to make this easier and/or any devices to help us out that won't be crazy expensive? I know the contractor can shoot this much easier, but again, we would like to have a bit more knowledge than we now have. As always, thank for any help with this.

You will be spending hundreds of thousands on building a new house, but want to skimp on the access?
You NEED to pay for an engineering/survey driveway design, with your steep terrain.
Water runoff will be your primary issue, and you certainly cannot want to be fighting that issue FOREVER!

Are you also considering building your house without a set of plans?

 

[s219]

Under optimal conditions you'll only get 10-15' accuracy from smartphone GPS, which would make it hard to use GPS altitude and position to accurately calculate grades over short distances. And the accuracy can be much worse if there is tree cover. However, the angle measurements of smartphone apps are extremely accurate. The Theodolite app can measure angles to 0.1 degree accuracy and has a grade option to directly read out in %grade. You can get a good quality tripod from Amazon for $25-35 and have a nice setup for measuring angles. I did this last year and was really impressed with the results. Beats renting a transit, which I used to do all the time.

 

[ruffdog]

You will be spending hundreds of thousands on building a new house, but want to skimp on the access?
You NEED to pay for an engineering/survey driveway design, with your steep terrain.
Water runoff will be your primary issue, and you certainly cannot want to be fighting that issue FOREVER!

Are you also considering building your house without a set of plans?

I agree^^^. Plan to cut trees far enough away from the drive so big trucks can get in. Make it easy for a ambulance to travel on. Now is the time to design it to be as much maintenance free as possible. A little forethought might eliminate some "should of/ could ofs".

 

[/pine]

I think there is a misconception of how a GPS device/app determines elevations...
All a GPS can do is determine geographical location...for elevations it must use third party data (nothing to do with GPS) i.e, data from topographical mapping that is correlated and interpolated...That is...once a location is determined it (device/app etc.) then relates that position to known elevations.

 

[Egon]

Dumpy level or hand level have worked in the past.

What you want to do is develop a road grade profile.

 

[shooterdon]

I am a recently retired land surveyor and the weak part of cheap hand held gps is the elevations. If the area is wide open, no trees you might get decent results but I would not count on it.

They make cheap hand held levels, like a small telescope, about 10” long. Usually no magnification. I would put lath in every so often, say 25 feet measured in, and start at the bottom and work your way up the hill. You will need to know how high your eye is and make a mark on the lath ahead of you with a helper and measure how high the mark is.

For example, your eye is exactly 6 feet high, you make a mark on the lath 25 feet away 1 foot above the ground. That means the ground is 5 feet higher in 25 feet which equals a 20% grade. Keep in mind you can not measure higher than you stand, so if the ground in 25 feet is 7 feet higher you will have to set lath shorter than 25 feet. Keep in mind it shoots level, not up or down hill. This method is not great but is very cheap. They also make hand levels that will shoot up hill and show a grade on a scale on the side but are hard to find these days.

Some counties and states have free topo maps available. You probably need a way to print them out to scale them though. The quality of there software varies also on if you can just get the measurements on your computer or need to print it out.

Of course a surveying or engineering company could survey and design something but not cheap.

I would follow this advice to get a rough idea of possible options for the drive. A bit time consuming but it should be reasonably accurate if you are careful.

One question, will the county require a survey to prove your grade is correct? In which case you have to pay for it anyway. If not, ask them how they determine the grade. Maybe they have a neat device you can rent.

 

[Jim Nelson]

I agree with Dodge Man &Egon about the hand level but you will also need a folding 6' engineers rule to determine the height you are shooting. I did this for years in the construction industry and with some experience and being careful you can get very close to the height you are measuring. I have seen good grade checkers find busts in surveyors staking several times on both road jobs and housing tracts. You do need to be sure your hand level is accurate and there is a procedure for that using 2 stakes. You would be better of seeing if you could find an old construction hand or grade checker to help you.

I worked with an old owner operator who had a couple of John Deere 450 dozers with dual slope boards and he'd could get his tractor set up cutting finish slopes and jump off the slow moving tractor and check his grade while the machine was chugging along. He was exceptional.