Outside my house and my neighbours houses (UK) is a stretch of about 35m x 7m of private road. I'm talking to various companies about them resurfacing the road. They are split into two groups:

  1. Some are saying the road is in a very bad state of repair, and needs to be planed off (i.e. the existing road surface scraped off) before laying a new base and top asphalt/tarmac surface.
  2. The others are saying the existing surface is generally ok to use as a base, and only about 10sqm needs to be dug out and filled where it's broken up. So they are saying they would just lay a new surface on top of the existing.

How do I know which is the right approach? What is the usual point at which a road is deemed to need digging up and rebuilding from the base layer?

  • It's possible that the discrepancy has to do with the size of the equipment being used. Company A may be using larger equipment, so removing the entire road is actually easier and cheaper for them than patching. Where as company B may use smaller equipment, so doing a patch is easier and cheaper for them. Or it could just be that company A wants to do a proper job (and doesn't trust the previous work), where as company B just wants to do the job as cheaply as possible (cheaply meaning least cost, not quality). – Tester101 Apr 19 '13 at 13:51
  • I should say that the quotation I've had to dig down is double the quote to just lay a new surface on top. I can't shake the feeling that vendor is simply creating extra work to create more business for himself, but it is hard for me to know. – Ollie C Apr 19 '13 at 15:45

Whether to plane the surface or not before an overlay is a complete judgment call. You are comparing the general condition of the current road in combination with it's current thickness. An overlay needs to bridge underlying imperfections and absorb differential movement. The more massive the underlying tarmac, the more likely it is to overwhelm the overlay's ability bridge and absorb. Which results in the cracks and such in the old surface reappearing in the overlay.

Planing the old material off reduces it's mass so the overlay has an improved chance of bridging and absorbing imperfections. Planing alone is commonly similar in cost to an overlay, so doubling the cost of the whole job sounds about right. The risk of not doing it is that the overlay is overwhelmed and imperfections appear prematurely. The next time around, planing WILL be required. Now you've paid three times the overlay cost in a short period. Paying for planing now can prevent paying for it in the near future.

The risk of planing is spending money when it is not required. If the overlay alone can absorb and bridge imperfections adequately, it will last just as long as if it were planed first, so planing is a waste of money.

It really takes someone with a lot of experience in road work to make this kind of judgment. There's no formula where you can enter the level of damage and the thickness and get an answer. I've seen well qualified roads people argue back and forth if planing is worth it or not, so it comes down to who you feel is most trustworthy and has the experience and judgment to honestly assess your situation and make a recommendation considering your needs and not their profit margin.

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Although you may have a feeling that the contractors proposing to do the full scraping are trying to drum up unnecessary work for extra pay, consider that they know that you're considering other bids. Anyone proposing more expensive work runs the risk of pricing it too high and not getting any work at all.

You also have to worry about low bidders: those who underestimate the job by cutting corners in order to out-bid the competition on price. Those who recommend just paving over the surface just just as well be suspected of trying to simplify the task to get the job.

I would suggest that you get a bid for identical or almost identical work from each prospective contractor. You can't compare two contractors on price, if they submit different proposals.

From each contractor, get a quote for doing a scrape and resurface, and just repairs. Then you can see who is expensive and who is the low-baller. Try to get a detailed quote breaking down the individual costs for the stages of repair, time and materials.

As far as which one to do, that is your call, but your choice of treatment for the road should not confine you to a contractor. They should all be capable of the same work.

The contractor who believes that the road needs to be scraped may not want to provide a quote for just repairs, but try to press them for it anyway so you have a more complete basis for comparison.

It may be the case that a road that does not need scraping does not actually need resurfacing at all. Either the road can be repaired, extending its service life by a few years, or else that life cannot be extended and it is replaced. The contractors who want to perform repairs and then lay a surface over top may in fact be the ones trying to drum up work. If the road is reparable, why does it need resurfacing, other than for cosmetic appearance? And if it is not reparable, how can you justify just coating over an irreparable road? You wouldn't paint over flaking, peeling paint! What good is cosmetic appearance if it doesn't hold up automobiles?

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