A geezer, a propane torch, and some flammable material. What could possibly go wrong?
Final steps: Tar and seal coat.
In this post, I finish the repair that I started in late spring, mending a badly deteriorated section of driveway with a half-ton (20 bags) of QPR asphalt cold patch (Post #1977).
As shown above, my driveway is still ugly, but it is a lot better than it was.
First up: Melting 90 feet of tar rope (three packages of Pli-Stix), as a general surface filler. This is actually kind of fun, in a little-kid-playing-with-matches way. For about the first ten minutes.
Useful observation: The bigger the torch, the faster it goes. (Duh.) My little Bernz-o-Matic brass torch head (~ 2.5 K BTU/H) was excruciatingly slow at melting the Pli-Stix tar (top line of table above). I bought a higher-output (7.4 K BTU/H) torch head to finish the job, melting in the Pli-Stix tar at a rate of around 25 feet per hour. With that, I did the entire 90 feet of tar crack-filler with a one-pound disposable propane cylinder. (N.B. a pound of propane has about 21.5 K BTU of energy.)
I don’t think you need one of those 500K BTU/H “ice-melter” torches unless you really enjoy buying propane. Plus, as I used it (on the surface, not lodged in a crack), the faster you go, the more of the tar ends up burning off. The Pli-Stix medium tar rope is only 3/8″ thick. If you get in a real hurry, you’ll end up turning the majority of the material into flame, heat, and smoke, instead of the liquid tar that you want. I’m not sure I could have used a bigger propane torch effectively in this surface-melt use of Pli-Stix.
I took the extra step of sealing the edge of the patch with melted tar, out of fear of freeze-thaw damage. It’s not clear that this is necessary, but this patch is laid directly on top of the surface of the old asphalt. If water gets between the two, I think there’s a good chance that freeze-thaw will pop the patch off. The tar should seal the most vulnerable spot for water entry, and feathers the edge a bit where the patch meets the pavement. (Note: This surface-melt use of Pli-Stix is completely contrary to the manufacturer’s directions. But it works.)
(Note: The patch is nowhere as thick as it looks in this picture. The apparent thickness is an optical illusion from the torch having blackened the edges of the asphalt patch material.)
(Second note: You need to buy a hose to connect a standard torch head (the screw-into-the-propane-bottle kind) to a propane bottle. You run the torch upside-down while melting the tar. You cannot do that (and never should!) by simply turning the propane-tank-and-torch upside down. I bought the Bernzomatic torch hose, and found the propane tank belt-hanger hook to be a handy add-on. Just hang a one-pound disposable tank on your belt, piped to any old torch head, and you’re good to go. I taped the propane hose to a stick to let me use the upside-down torch head from a standing position.)
The ONLY way the manufacturer says to use this is to place it in a crack in the asphalt (1/2″ to 1″ range for the medium size), slightly below flush, then melt the top to form a seal. That’s not how I used it. I did some crack-filling, but mostly I just used it as a ready source of tar. That, because I used it to seal, on the surface, all around the edges of my patch. This is NOT a use recommended by the manufacturer.
And finally: Coating the patch with Latex-ite 10-year driveway sealer.
Useful observation: Flat tools don’t work for spreading stuff on curved surfaces. I used the traditional squeegee method for spreading driveway sealer. It was a total train wreck on my non-flat driveway patch. The resulting coat of sealer was far too thick, and uneven to boot. I ended up dragging a broom across it to try to even it out and save the surface finish, but it developed craquelure anyway as the thick portions dried. The only solution for that is to live with it until it wears off. Or re-coat, which I ain’t gonna do.
I’m not sure what the right tool is for spreading gel-type seal coat on a non-flat surface. If I had it to do over, I’d try a short-nap paint roller. And I’d use cheaper, thinner sealer. The only thing I can tell you for sure is that a squeegee doesn’t work if your driveway surface isn’t close to dead flat in at least one dimension. To add insult to injury, it also costs you money in excess sealer used.
N.B., the gel-type 10-year Latex-ite did nothing to hide the patch, or any other flaws in the underlying pavement. As advertised, it does fill cracks up to 1/8″ wide. What the manufacturer doesn’t tell you is that it fills them, then telegraphs their presence right up to the surface finish.
As you can see above, I started off with a pretty grim-looking piece of pavement. YMMV.
Conclusion
I’m still kind of ambivalent about this repair.
Maybe the right thing to do was to call in a pro and have that section of driveway torn up and replaced. But, for a lot of reasons, putting in a perfect new hot-laid section of asphalt driveway made little sense. In the context of the rest of this 60-year-old driveway, patched-but-serviceable seemed like a better fit. And that seems to be what I’ve gotten.
Placing a surface patch overtop badly alligatored asphalt was a lot less work, for a DIY repair, than the alternative of digging up that entire section of driveway and placing a full-depth patch. All that alligatored asphalt was firmly embedded in the clay soil underneath. The surface-laid patch also used a fraction of the materials that a full-depth, level-to-the-existing surface repair would have used. (I would guess something like 20% of the material that a full-depth patch would have required. Which matters quite a bit if you’re moving it in 50-pound bags). And it avoided having to dispose of the old asphalt and the dirt underneath, not to mention the having to buy and place gravel underneath any full-depth patch.
It’s probably worthwhile do at least a pro-forma calculation of the amount of asphalt involved. Assuming that an asphalt company would replace literally just the ~150 square foot area covered by the patch, to a “standard” depth of four inches, over a gravel base, that would require 50 cubic feet of asphalt (plus roughly the same amount of gravel under it). By contrast, the 20 bags of QPR work out to be less than 7 cubic feet, or about 13% of the volume of asphalt that would have been used in a full dig-and-repave fix for the footprint of the patch.
All in, the total dollar cost for this ~150-square-foot patch (plus cracks in the surrounding pavement) was about $500. About $400 for the asphalt patch, $45 for the tar, and $60 for the seal coating. The tar is optional. If I had to guess the total time, excluding time for driving out to buy stuff, I’d guess 32 hours: Eight for surface prep, 16 for laying and tamping the patch, 8 for tar-based crack-fill and seal coating. Throw in another $20 for the broom/squeegee thing used to rescue the surface — that isn’t ever going to be usable again. Toss in 10% for rounding and tax. Maybe better to call it $600.
I may have underestimated the surface prep time. As I recall, all in all, I shoveled off the vegetation and mud with a sharpened square-nose shovel. Hosed it down a couple of times. Ran a weed whacker a bit. Probably swept once. Re-hosed it. Re-swept it. (All oriented toward getting the packed grit out of the surface and particularly the bottoms of the puddles). Then sprayed high-concentration salt water, and spread rock salt, to try to kill whatever plant roots were left. Swept up that mess. And proceeded to place asphalt. In hindsight, make it 40 hours total. Exclusive of time spent deciding on and purchasing materials. But it’s not like I work fast, either.
But in addition, with a hot-asphalt full-depth patch, I’d probably have had to dig up two or three times that area, in order to remove the entire section of driveway that had sunken over time, and bring the entire area up to the level of the rest of the driveway. Arguably, my minimum hot-laid full-depth asphalt fix would have involved about 300 square feet of driveway, and so more than 20x as much asphalt as I used with surface-laid QPR. It would have produced a much nicer-looking fix, but at a going rate around here of $10 to $12 a square foot for driveway replacement, I think my minimum professional full-depth repair would have been in the neighborhood of $3.5K. It would undoubtedly have looked better, but I’m not sure it would have looked $3K better than QPR.
That said, a surface-laid patch is an inferior approach, compared to a more labor-intensive and materials-intensive full-depth patch. The whole time, you have to plan for how water will run off or around the patch. And, because it sits proud of the existing pavement, the edges of the patch will catch and hold a little bit of water, no matter what. Plus, you can’t disguise the fact that the surface has been patched.
But my main concern with this approach is the potential for freeze-thaw damage. That’s why I went to the extra step of sealing the edges with tar. And that’s why it was critical to get this heavily seal-coated before winter sets in. I want as little water as possible to get underneath this patch, even if the underlying pavement is all broken up and so should drain water. I would not surface-patch over sound asphalt, where there is no place for the water to go if it gets under the patch.
All I can do now is wait and see what happens this winter. I’ll try to remember to come back to this post in spring 2025. For sure, if the patches fail from freeze-thaw, I’ll come back and note that here.
As an addendum, I should say that I considered but dismissed a lot of the “quick-fix” methods for dealing with alligatored and cracked pavement. For example, the pour-in liquid crack fillers only work on small cracks, and typically only last a year or two. I also rejected the paste-type or gel-type spread-overtop alligatored pavement fixes, not only because they too seemed less-than-permanent, but also because I’d have had to fix the pavement first (e.g., fill in where chunks were missing) before I could use that stuff. In the end, putting a solid asphalt patch on top of the alligatored pavement seemed like the best value in terms of longevity, cost, and a tried-and-true product. Assuming it doesn’t come apart over the winter.
Addendum: The problem with DIY on the internet.
The problem is that nobody tells you that most internet advice you get for driveway repairs — including advice from the manufacturers — simply does not work on a badly deteriorated driveway.
You can find all kinds of advice on driveway maintenance on the internet. And all of it seems to address problems that were tailored to the solution offered. Basically, you start off with some minor, defined problem on a driveway, and you fix it.
I can’t blame YouTubers for doing that. In this instance, and more generally. Nobody wants to spend their time watching somebody do a failed repair. But sometimes, knowing what to avoid is almost as valuable as knowing what works.
My main point is that you rarely see content about people dealing with a truly screwed up mess like my (former) driveway. One that’s never going to look perfect when repaired, short of outright replacement. One where the main goal is to be able to get to the garage without weed-whacking the pavement first.
This is a problem because many fixes that work perfectly on a reasonably sound driveway turn out to be (less than) useless on a roller-coaster alligatored driveway surface like mine. Almost the only useful advice you’ll get is to dig it up and replace it.
In any case, that’s how I ended up using a squeegee to try to spread thick driveway sealer, on this messed up driveway surface. Against my better judgment. That was literally the only method that the manufacturer recommended. It’s the only method you’ll see for videos about driveway surfacing, unless you explicitly look for something else.
So I tried it. And FYI, it didn’t work.
Surface-laying Pli-Stix, on the other hand? Worked like a charm, even if that’s not how you’re supposed to use the stuff.
