Building detached Garage (impervious cover) (Austin, Tool: apartment, houses, landscaping)

[laxman1100]

I live in Zilker Park and I'm looking to build a permanent detached garage. I have a few issues I need to contend with.

Like most houses in my area, my garage will be in my backyard, which means, I have a long driveway run to the garage itself. I'm currently at 45.3% (3490 sqft) impervious cover, but 33% of that (1138 sqft) is driveway.

I'm 585 sqft short in impervious cover allotment to build a bigger garage. My questions are:

How hard is it to get a variance?
Do I have options as far as materials that would reduce my impervious cover?

Thanks for any help/advice.

[OpenD]

The best option is probably to make the driveway permeable... a gravel driveway, or permeable pavers.

[laxman1100]

It sounds like doing driveway runners is our best bet. I hate the way they look, but I guess I don't have a choice.

Am I better off doing pavers or concrete?

[EzPeterson]

Pavers for sure - it's easier to keep them level as the years go on, and if one breaks - easier to replace! It's a bit more work putting them in, but easier to maintain.

[achtungpv]

Originally Posted by OpenD

The best option is probably to make the driveway permeable... a gravel driveway, or permeable pavers.

I've never checked but I've been told that Austin does not consider gravel to be permeable. It's so stupid an idea, it makes perfect city government logic.

[CptnRn]

Originally Posted by achtungpv

I've never checked but I've been told that Austin does not consider gravel to be permeable. It's so stupid an idea, it makes perfect city government logic.

It appears that in some cases it is excluded from "Impervious cover" but if used for a driveway may still have to be counted.

http://www.amlegal.com/nxt/gateway.dll/Texas/austin/thecodeofthecityofaustintexas?f=templates$fn=defau lt.htm$3.0$vid=amlegal:austin_tx$anc=
§ 25-1-23 IMPERVIOUS COVER MEASUREMENT.

(A) Except as otherwise provided in this section, impervious cover is the total horizontal area of covered spaces, paved areas, walkways, and driveways.

(B) Impervious cover excludes pools, ponds, fountains, and areas with gravel placed over pervious surfaces that are used only for landscaping or by pedestrians.

I can see that making a certain amount of sense, if the gravel surface is used for a driveway automobiles will compact the soil and it will shed water rather then absorb it.

[buffettjr]

Originally Posted by laxman1100

I live in Zilker Park and I'm looking to build a permanent detached garage. I have a few issues I need to contend with.

Like most houses in my area, my garage will be in my backyard, which means, I have a long driveway run to the garage itself. I'm currently at 45.3% (3490 sqft) impervious cover, but 33% of that (1138 sqft) is driveway.

I'm 585 sqft short in impervious cover allotment to build a bigger garage. My questions are:

How hard is it to get a variance?
Do I have options as far as materials that would reduce my impervious cover?

Thanks for any help/advice.

You have no options for reducing impervious cover with the garage itself, but as others have stated you can tear up your existing driveway and use impervious cover for the new run back to the garage.

As for the variance, it can be difficult and time consuming. IIRC, your variance has to be approved by the city, but a notice is also sent out to everyone who lives around you and they all have to approve as well. Someone correct me if I'm wrong, but my understand is that if even one person who is notified objects then the entire project is off.

I explored this issue when I was considering a detached garage in the Zilker neighborhood. Builders advised me that it is a lengthy and frustrating process and that you're much better off making decisions that do not necessitate a variance.

If you're curious I have not yet build the garage. I was considering building a garage apartment above it, which is why I would have needed the variance. My lot falls short by 150 sq ft for allowing a second living unit.

[laxman1100]

Thanks for the responses, I think I'm going to take everyone suggestion on the pavers. Another question: What is the rear setback for a garage? Also, does anyone have the definition of an "accessory" building?

Context for the question is that I want to build the garage with flex space (~300 sqft) that I want the option to convert to an office and potentially plumb for a toilet.

[CptnRn]

I expect that building inspection will consider pavers as a paved area, 100% impervious cover.

With some work you might be able to find the answers to your questions here Online Tools & Resources | AustinTexas.gov - The Official Website of the City of Austin

The FAQ here FAQ | AustinTexas.gov - The Official Website of the City of Austin under Uses and Development Standards on my property – What is permitted? if you click on Residential Zoning the pdf file that downloads says that for most residential property the interior side property setback is 5', a street side yard setback is 15' and the rear yard setback is 10'. I don't the rear yard setback has always been 10' as there are several houses in my neighborhood with the back of the garage closer to the rear property line then that.

[CptnRn]

Looking for a better definition of impervious cover I found this:

http://www.amlegal.com/nxt/gateway.dll/Texas/austin/title25landdevelopment?f=templates$fn=default.htm$ 3.0$vid=amlegal:austin_tx


§ 25-8-63 IMPERVIOUS COVER CALCULATIONS.

(A) Impervious cover is calculated in accordance with the Environmental Criteria Manual.
(B) Impervious cover calculations include:
(1) roads;
(2) driveways;
(3) parking areas;
(4) buildings;
(5) concrete;
(6) impermeable construction covering the natural land surface;
(7) for an uncovered wood deck that has drainage spaces between the deck boards and that is located over a pervious surface, 50 percent of the horizontal area of the deck;
(8) interlocking or permeable pavers, except up to 20 percent of the area of the pavers may be excluded in calculating impervious cover if the pavers are approved by the director for recharge enhancement under Section 25-8-151 (Innovative Management Practices); and

Given that they count a wood deck with spaces between the boards as 50 percent impervious cover, I can't imagine them not counting pavers with narrow cracks between them.