Shared Knowledge

"Asphalt Driveway Repair - How to fill a Pothole or Bad Section of Asphalt"

25 January 2013




I have 150 foot long X 8 feet wide driveway with additional 40 foot wide X 10 feet deep parking area.

Was resurfaced in 1990.

Was hot sealed in 1990.

In 2012, large tree right beside driveway was blown over in storm and driveway severely turn apart.

As driveway level with garage, top layer would have to be removed to re-asphalt and estimated cost was $10,000.


How to fill a pothole or replace a bad section of asphalt:

You are going to need a pair of work gloves as asphalt is messy (cheap $3 of $4 kind).

You are going to need a cheap set of chisels and a nail-type hammer.

If you have a large section to replace, you will need a power saw with a stone cutting blade on it. Stone cutting blade will cut through asphalt and give you a nice straight edge.

You going to need a 3 pound hammer to do tamping.

You going to need a sledge hammer to do tamping.

You might need a 1foot X 1 foot dirt tamp but do not buy unless when you have hand tamped, you think you need the dirt tamp.

Going to need cold-patch asphalt. This is normally sold in 50 or 60 pound bags. Amazing how little one bad actually covers or fills once it is properly tamped but start out with one bag and buy more as needed.

Going to need a trash-can or other to hold asphalt you going to dig out of pothole.

Now at site of pothole, use chisel to dig out asphalt around edge of hole such that you get a straight edge down for at least 2 or 3 inches. As stated on the bag, cold-patch asphalt wants a straight edge to fill and not a hallow.

Test the center of the pothole with your chisel and take out all loose or crumbing asphalt. Patch, repair is not going to hold if foundation under new asphalt is not solid. In my case, I found that in some places I have 4 layers of asphalt with the layer under the top most being the worst. "Bad" asphalt will literally crumb when you hit it with a chisel.

If when you remove all bad asphalt from your pothole, you are down to bare dirt, you really should dig the dirt out for 4 or 5 inches, fill with loose rock (blue stone or other but not lava rock), water good and then tamp down. The rock will give you a good foundation and although not as solid as concrete, with the rock "watered" in properly, a decent enough foundation will be there for you new asphalt.

With pothole cleaned out and with a solid base, begin to add new asphalt, 2 or 3 inches at a time. Level, more or less, with your gloved hand.

Now take the 3 pound hammer and begin to tamp the new asphalt down. Tamp especially well along the edge of the pothole.

Tamp down the new asphalt with your 3 pound hammer until it feels solid and has begun to resist additional tamping.

Now use the sledge hammer and sitting near the hole, use the sledge hammer as a hand hammer. The sledge hammer has a larger head than a 3 pound hand hammer and so will help tamp new asphalt more evenly.

Once you have new asphalt tamped down, add more to hole. Depending on depth to be filled, no more than 2 or 3 inches at a time before tamping again.

As tamped new asphalt begins to get level with surrounding asphalt, slow on adding new asphalt but if you have tamped well as you filled the hole, you can probably overfill the hole by 1/2 to 1 inch and easily tamp down to get the top of the pothole even with surrounding asphalt.

Finally, when you have the pothole filled like you want it, begin to add some new cold-patch asphalt around the edge and then tamp this down. This will help give a tight seal on the edge of the hole.

If your patch is not level, you can add cold patch as needed and tamp. You can add cold-patch asphalt to existing patch until the newly added cold-patch looses its "oiliness". Once cold-patch looses its oiliness, you are better off tamping down high areas than trying to fill or raise low areas.

No matter how much you tamp down cold-patch asphalt, you can always tamp it down more. This holds true for probably 60 days at least.


Replace a bad section:

 If the area to be repaired is larger than a pothole or is a large pothole, you should cut the asphalt with a power saw and a stone cutting blade.

What you do is get some sidewalk chalk and a straight piece of wood long enough to be used as a chalk straight edge.

Then looking at bad section of asphalt, figure out how you want to cut it out such that you can use a sledge hammer head to help tamp down new asphalt. What I mean by this is, the cut out should be at least 3 or 4 inches wide.

Using the chalk and straight edge, mark where you want to cut.

Now take your power saw and adjust the depth of the cutting blade. You want to adjust so the cutting blade is deep enough to cut most of the way through the top layer of asphalt but not so deep as to make cutting incredibly slow or cut the layer of asphalt that might be below the defective layer. Once you have cut out a section and actually gotten some of the bad asphalt out of the cut section, you might see you needed to increase or decrease the depth of the power saw blade.

Now wearing a breather mask of some kind, gloves and perhaps something to cover your arms, use the power saw and begin to cut asphalt. There will be a lot of dust and cutting will be slow but your power saw will cut asphalt.

Now take a chisel and hammer and insert chisel edge into one of your cuts and try to lift up the cut section. If it will not lift, you can try using the chisel anywhere in the cut section to cut across and then perhaps get a part of the cut section to lift.

If your cut section does not want to lift out one way or the other, it is possible that your saw blade was set to too high and your cut section has not been cut all the way down. So adjust your saw blade down perhaps a quarter inch and cut all lines again. Insert saw blade into a cut and make sure you have plenty of forward pressure on the saw before you squeeze the trigger or the saw might try to buck back towards you.

After you have cut all section lines again, try to get the cut section out.

Once you have all asphalt in the cut section out, check out the underlying asphalt, if any. In my case, in some places I had 3 and even 4 additional layers of asphalt and the one immediately under the section removed was defective. How to determine if defective?  Use a chisel and if the underlying asphalt chucks out too easily, you are going to have to remove it as well but this time you can not use the saw, just the chisels.

Use the chisels to break chucks of the defective asphalt out of your cut section hole making sure you get a nice straight edge on all cut hole edges.

If you find dirt under the section you remove, you should dig down a couple of inches and then fill hole with rock, water rock in, tamp down before adding new asphalt.

With a solid base (a good underlying asphalt layer or a well tamped rock base, begin to add new asphalt to the cut section hole, a couple of inches of new asphalt at a time.

Now using 3 pound hammer, begin to tamp down asphalt making sure you get the edges tamped down well.

After 3 pound hammer tamp, use the sledge hammer to tamp again. Here you use the sledge as a wide headed hammer, not swinging the sledge from the handle, just like a nailing hammer.

Add more fresh asphalt to cut section hole and tamp well.

When you are less than an inch from having a full hole, add more asphalt such that you have at least 1/2 to 3/4 inch too much and then tamp it down flush with surrounding asphalt. As you tamp, if a depression forms, fill with more asphalt and hand tamp with 3 pound hammer and sledge.

Once you have cut section filled and tamped, you can use a 1foot X 1 foot dirt-type tamp to help level the section asphalt with surrounding asphalt.

Finally, if you a mind too, you can use Pli-Stix around the edge of the cut section to rubber seal the edges. I do not do this.





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