Quick building question.

[Rum Runner]

Hi all,

It's been awhile since I last visited, been busy, busy, busy...LOL. Anyway I have a building/garage question for the people who may know. I want to extend my garage another 14+ feet to about the end of my driveway. My question is can I extend the garage over blacktop? The structure itself will be supported around the parimeter with concrete footer. The only thing that will be blacktop is what will be in the garage itself. So I guess I'm asking if I can have a blacktop floor in my garage? Is what it boils down to. I appreciate your time and attention.

Thanks Again,

[Mopar05]

You would need to check with the local building inspector for the legal answer to this. My dad has blacktop in his four stall pole barn, so I'd say do what you want. Concrete is much stonger though. Not to expensive to have popured, just alot of work if you do all the prep yourself.

[HeminatorTom]

Code will not restrict you from using the blacktop as a base floor, as long as the perimeter pour meets local code. I see a lot of garages that have been extended over asphalt in my work as an adjuster. I see nothing in code that will restrict you from doing that. Just remember that if this is an enclosed garage that your going to get that asphalt odor in the hot summer. Of course you can seal the asphalt with a non asphalt sealer, or put tile on top of it, if it is solid and not cracked.

Tom's right as far as most codes are concerned. If your going to be doing any kind of mechanic work you would be well advised to overlay it with 4" of concrete. Asphalt and solvents or gasoline don't work well together. The oils in the asphalt will dissolve. Again it depends on how your going to use it.....and of course how much money you have to spend.

[ArcticWolf]

Doug..

He wouldn't need to go with a 4" slab on top of it, a 2" slab with wire mesh for reinforcement would work just as well - a topping slab, just make sure you use at least a 3000 psi concrete mix. It would still be expensive (depending on where you live and the cost of concrete) but like the others said, anything you use won't be likely to damage your floor. Oil, gas, diesel, solvents will eat the bitumen in the asphault and can severely weaken it - would you want pot holes in your garage?

You will most probably require to get a building permit for the addition or expansion on your garage.

If you opt not to go with a topping slab, remember that during hot weather the asphault will soften and if you have a vehicle up on jackstands or even a motorcycle on a kickstand, that they will sink and/or fall over.

(I've been a construction special inspector for the last 21 yrs)..

[SLAMLLC]

Great advice from all. The honest and simple truth is it is going to be extreemely difficult if not impossible to excavate for the footings without damaging the asphalt. You are going to have to cut the asphalt in order for it to not break along the trench for the excavation. It could still break and you will not be able to pour the footing or foundation that close to the edge of the asphalt and still backfill up to the new foundation inside the garage. So you will likely need to repave 3 feet of asphalt around the perimeter inside the garage in the end anyway to try to get it to match/ look good. At that point you should just tear it out anyway.