Permeable Driveway Options

[LimitedReality]

In our township in PA anything over 1000 sq. feet requires engineered water infiltration (read: $$$). My garage is 784 sq. feet but tying it into the driveway puts us almost 200 sq. ft. over the limit. I was wondering if other folks have had similar problems and how they solved them? (Or if anyone in PA know's an engineer who doesn't work for an arm and a leg.)

The township considers a traditional stone driveway impermeable, but I've read that TrueGrid and DuPont DPGG-5055 Grid products when used with loose stone are considered permeable. Anyone have experience with either or similar products?

This will be for a car, light truck, and motorcycle garage. The driveway area is 18'x22'. Appreciate any feedback you have.

 

[Stellaontap]

Hi Limited, google turf stone....I am pretty sure it will meet permeable paving requirements and should be available in your area.

Eric

 

[Hilltopmasonry]

There are plenty of brick (paver) choices that are permeable....Google Unilock and check out some of their permeable products



Sent from my iPhone using Tapatalk

 

[malibu101]

Most times the availability, cost, installer knowledge, and suitability for local conditions play a large role in what to use for your area.

Can you find out what others have done in your township to meet the requirements?
Since it's a requirement, you're not the first person to have ran into this; Maybe ask for a price from a couple of local excavators?

Does it need an engineers stamp?
If it does, it's normally pay up and move on.

 

[RSr]

de-couple the projects? Go back after your building is complete and certificate of occupancy issued and apply separately for the driveway a while later (maybe a year? or maybe the driveway section is so small it doesn't even require a permit by itself). I have to deal with the same thing over in western PA but my township is anything over 400ft sq requires engineered storm water management.

 

[malibu101]

de-couple the projects? Go back after your building is complete and certificate of occupancy issued and apply separately for the driveway a while later (maybe a year? or maybe the driveway section is so small it doesn't even require a permit by itself). I have to deal with the same thing over in western PA but my township is anything over 400ft sq requires engineered storm water management.

Maybe. Seriously, smart thinking!

Just ask---
"Hi Mister local zoning officer,
How long until 2 projects are not considered as 1 so I can avoid your rules?"

 

[steveo1o9]

Most times the availability, cost, installer knowledge, and suitability for local conditions play a large role in what to use for your area.

Can you find out what others have done in your township to meet the requirements?
Since it's a requirement, you're not the first person to have ran into this; Maybe ask for a price from a couple of local excavators?

Does it need an engineers stamp?
If it does, it's normally pay up and move on.

This.

As an engineer who works predominantly in stormwater depending on what they actually want this could cost you big bucks. Ask specifically what they want to see, they most likely just want some permeable pavers or something rather then a complete treatment system.

What is the driveway you are connecting to made of?

 

[BucksCtyMike]

There should be a small project stormwater management option for homeowners in your township. While an engineer or architect could help, I don't think they are necessary for approval.

If you meet the requirements, and you probably do, it'll require some basic calculations of water runoff and BMP as to how you will handle the additional runoff ... rain garden/dry well/ etc. Township should have a handout from epa that explains all of this laymans terms and explains your options for BMP.


Also, EPA is requiring local muni's to enact stormwater mangement practices on their residents as conditions of the muni's own wastewater permits from the federal government.




Sent from my iPad using Tapatalk

 

[RSr]

There should be a small project stormwater management option for homeowners in your township. While an engineer or architect could help, I don't think they are necessary for approval.

If you meet the requirements, and you probably do, it'll require some basic calculations of water runoff and BMP as to how you will handle the additional runoff ... rain garden/dry well/ etc. Township should have a handout from epa that explains all of this laymans terms and explains your options for BMP.

Sent from my iPad using Tapatalk

My township has these available but then when I talked to them they still required the plans to be stamped by an engineer... infuriating. The OP can check out my build post about storm water management to get an idea of whats involved and the cost I was quoted from a few firms.

Stuff you can read about small project stormwater managment, including permeable pavement.

https://www.ecode360.com/attachment/FR0955/FR0955-178f%20App%20F%20Planning%20Guidelines%20for%20Small%20Projects.pdf

 

[johninct]

de-couple the projects? Go back after your building is complete and certificate of occupancy issued and apply separately for the driveway a while later (maybe a year? or maybe the driveway section is so small it doesn't even require a permit by itself). I have to deal with the same thing over in western PA but my township is anything over 400ft sq requires engineered storm water management.

Do this.

 

[CraigStu]

I would ask the county for a list of approved materials. It doesn't matter what any of us think, only what they think. In Md, within 1000feet of the water they don't consider even gravel as permeable.

 

[chaosracing]

OP....what township and county do you live in? Some areas you can just get away with an infiltration pit (basically a big hole in the ground lined with fabric and filled with 2b stone) that all your storm water goes to. Permeable paving can be very expensive. You do not need an engineer unless they are requesting specific data such as water infiltration rates and run off rates, which are easy to obtain yourself.
Techo bloc has designs online for permeable paving, but there are many different types(from other manufacturers).
I am curious as to why they claim a stone driveway is not considered permeable? Because if thats the case, then the only thing they would really accept would be some kind of soil and sod set up.

 

[bighouse01]

There is a blacktop mix available that allows water to flow through. Doesn't look as smooth as normal blacktop. It uses larger stones and less asphalt. Talk to a blacktop guy. A freind of mine had his driveway done with this since his town didn't allow the runoff.

 

[chaosracing]

There is a blacktop mix available that allows water to flow through. Doesn't look as smooth as normal blacktop. It uses larger stones and less asphalt. Talk to a blacktop guy. A freind of mine had his driveway done with this since his town didn't allow the runoff.

Don't think anyone in PA uses that. Our freeze thaw cycles will destroy that the first year its installed.

 

[BucksCtyMike]

The standard I've seen is generally anything from 1k-5k does not need an engineered site plan submitted for permit. You will need to do volumetric control plans and calculations, but you don't need an engineer for that.

OP, I would double check this requirement.

Edit: assuming residential. If you are zoned commercial, youll need an engineered site plan for 1k-5k plans.

And per the split job ideas, most muni have provisions in the code for ideas like that. They'll ask for site plans and calcs when you apply for 2nd permit


Sent from my iPad using Tapatalk

 

[2level]

One thing to keep in mind is that a permeable driveway often creates a maintenance headache and a safety issue. Ice is more likely to form/stay put, and moss can be a constant battle and a major slipping hazard too. Is there a possibility that a dry well(s) will serve to meet the water runoff requirements?

 

[RSr]

And per the split job ideas, most muni have provisions in the code for ideas like that. They'll ask for site plans and calcs when you apply for 2nd permit


Sent from my iPad using Tapatalk

It wouldn't surprise me but I'm curious what that language would look like as an ordinance. Any examples of how that's been codified?

 

[BucksCtyMike]

It wouldn't surprise me but I'm curious what that language would look like as an ordinance. Any examples of how that's been codified?

Most ordinances will specifically address site development that occurs in stages. Obviously it a case by case decision, but expanding a driveway and building a garage is likely to classified as one staged development and might be tough to argue against.


Quick copy paste from my local township:
5. For all regulated activities, implementation of the volume controls as listed in this Chapter is required.
6. Impervious Areas.
A. The measurement of impervious areas shall include all of the impervious areas in the total proposed development even if development is to take place in stages.
B. For development taking place in stages, the entire development plan must be used in determining conformance with this Chapter.
C. For projects that add impervious area to a parcel, the total impervious area on the parcel is subject to the requirements of this Chapter.
7. Stormwater flows onto adjacent property shall not be altered without written notification of the adjacent property owner(s). Such stormwater flows shall be subject to the requirements of this Chapter.
8. All regulated activities shall include such measures as necessary to:
A. Protect health, safety, and property.




Sent from my iPad using Tapatalk

 

[steveo1o9]

OP....what township and county do you live in? Some areas you can just get away with an infiltration pit (basically a big hole in the ground lined with fabric and filled with 2b stone) that all your storm water goes to. Permeable paving can be very expensive. You do not need an engineer unless they are requesting specific data such as water infiltration rates and run off rates, which are easy to obtain yourself.
Techo bloc has designs online for permeable paving, but there are many different types(from other manufacturers).
I am curious as to why they claim a stone driveway is not considered permeable? Because if thats the case, then the only thing they would really accept would be some kind of soil and sod set up.

A gravel drive is only permeable for a short time. After being driven on it will compact to as hard as pavement which is why it is considered impermeable.

One thing to keep in mind is that a permeable driveway often creates a maintenance headache and a safety issue. Ice is more likely to form/stay put, and moss can be a constant battle and a major slipping hazard too. Is there a possibility that a dry well(s) will serve to meet the water runoff requirements?

Permeable pavement should not form ice since water does not sit on the surface. That is assuming of course the subbase infiltrates. Any permeable surface over soils with poor infiltration is a waste. The only real maintenance is vacuuming the surface yearly to remove fines from the voids.

 

[BucksCtyMike]

Was also going to say that, gravel or crushed stone is usually considered non permeable in many of these ordinances.


Sent from my iPad using Tapatalk

 

[bighouse01]

Don't think anyone in PA uses that. Our freeze thaw cycles will destroy that the first year its installed.

It's been on his driveway for 4 years in NY. Still looks good!!

 

[RSr]

Thank you Mike for the example. You don't know what you don't know until you know.

I'll be parsing through my townships ordinances to see how/if they enacted similar restrictions. I feel local government is extremely poorly equipped to deal with these issues in a reasonable fashion. They are basically trying to limit their liability when their hand is forced to enact controls and they err very far on the side of restriction/caution.

 

[BucksCtyMike]

Thank you Mike for the example. You don't know what you don't know until you know.

I'll be parsing through my townships ordinances to see how/if they enacted similar restrictions. I feel local government is extremely poorly equipped to deal with these issues in a reasonable fashion. They are basically trying to limit their liability when their hand is forced to enact controls and they err very far on the side of restriction/caution.

Unfortunately, you are correct. The ordinances are written in attempts to cover wide areas of possibilities and situations.

And sometimes they completely get blindsided by unforeseen situations and have very little recourse. Cell phone data repeaters on new telephone poles under state utility codes caught many muni's off guard.

Homeowners were literally waking up to new poles being placed in front/rear of their homes with no notice. And there was little they could do because there was no local ordinance to govern such situations. It is/was a mad scramble to write and enact the ordinances.




Sent from my iPad using Tapatalk

 

[chaosracing]

Thank you Mike for the example. You don't know what you don't know until you know.

I'll be parsing through my townships ordinances to see how/if they enacted similar restrictions. I feel local government is extremely poorly equipped to deal with these issues in a reasonable fashion. They are basically trying to limit their liability when their hand is forced to enact controls and they err very far on the side of restriction/caution.

I will 2nd the you are correct. In my township, a developer wanted to put in a warehouse. They would have done severe cuts on the property just to level it out. Locals got 2 lawyers involved (one a municipal type and the other a civil) after much back and forth, it was shown that some of the ordinances were not being followed (fault of the zoning planner, that got fired beginning of year). During and even after that battle, we have been finding out that the township is ill equip in what actual ordinances are to be followed. Storm water containment being one. Part of the problem is here in PA, every 10 years the storm management stuff needs to be updated on a local level. DEP has now put into place strict rules to follow, and the townships are struggling to figure out how to follow and or enforce the new laws. There really is no clear direction. Agriculture, residential, commercial and industrial each has its own, along with area disturbed.

 

[chaosracing]

OP are you sure you really need permeable paving or a retention system? Double check with your townships zoning and building inspector (zoning should really know) I had the former zoning department (2 years ago) tell me that yes I needed a storm water management system (even though I am on 3 acres and the water would not run off to neighboring property anyway) The last zoning people said I did not need anything, even any temporary silt fence/straw bales (reinforced by the permit)

 

[2level]

A gravel drive is only permeable for a short time. After being driven on it will compact to as hard as pavement which is why it is considered impermeable.



Permeable pavement should not form ice since water does not sit on the surface. That is assuming of course the subbase infiltrates. Any permeable surface over soils with poor infiltration is a waste. The only real maintenance is vacuuming the surface yearly to remove fines from the voids.

Snow sits on the surface, ice layers on top of the snow, slowing down the melt. The vacuuming can be very time consuming/expensive; not always possible to get done before a snow event, also not very effective on moss. I see that you didn't address the moss issue...and then there is the high water table issue.

 

[steveo1o9]

Snow sits on the surface, ice layers on top of the snow, slowing down the melt. The vacuuming can be very time consuming/expensive; not always possible to get done before a snow event, also not very effective on moss. I see that you didn't address the moss issue...and then there is the high water table issue.

In theory as the snow melts it drains through the pavement eliminating ponding and ice. Not sure how ice on top of the snow is something caused by the permeable pavement itself. Permeable pavement is best used in areas with good infiltration coupled with a stone reservoir under the pavement. Infiltration is not suitable in areas with a high water table and typically 2ft of separation is required from the seasonal high elevation. If moss is an issue then the pavement and soils must be saturated and this practice is not best suited for this area.

I am not a big proponent of permanent pavement / concrete and only design it as a last resort. I also do not feel it is feasible to ask a homeowner to construct a properly functioning permeable system just for a driveway.

I am sure the town just wants to reduce the impervious areas by offsetting with permeable materials, overlooking the performance. Form over function.

 

[LimitedReality]

Wow thank you all for the replies. To try to catch up:

RSR - Several folks I've spoken with suggested the route of doing the garage now and doing the drive later. It's clever, but I really don't want to break the rules and risk a fine later when I either need to pull a permit for something else or go to sell the house.

Steveo1o9 - Big bucks is right. I've called 8 different engineering companies. Only two would even do residential storm water, and the one opted out when they heard it was my township. The other came back at $4-5k which is way out of budget. The existing drive is asphalt and predates storm water so it's grandfathered in is my understanding.

BucksCtyMike - The small project storm water option is a 10x10x5 infiltration pit but it's only valid up to 1000 sq. feet. The township said anything over requires an engineer (like RSR confirmed). Your right that this is ultimately going to be a larger pit or a rain garden but I need an official to design it. It is a residential area.

chaosracing - I'm on 2+ acres and yea they're saying I need storm water management. I was trying to avoid it by getting a permeable drive to avoid hitting the 1000 sq. limit since I can't seem to find anyone reasonable to help with the mgmt. option.

I've asked the township for a recommendation for local companies that do residential storm water but have received nothing back.

Anyone in PA know a guy or company that'd do the storm water design/stamp work for a reasonable price?

 

[BucksCtyMike]

What part of PA?


Sent from my iPad using Tapatalk

 

[LimitedReality]

York

 

[RSr]

I'm assuming your on the east part of PA so I doubt the company I dealt with would be interested. If you already have a primary garage then I'd be inclined to submit it as a workshop and install a ribbon driveway that keeps you under the ft² limit. You could always go back and add a permeable driveway (like the plastic grid grass grows through) in between the ribbons.

I feel your pain...