Weed Killer Spray prior to Tarmac

Fracking Cylon

Hi, getting quotes for tarmac at the moment. 1 thing that seems to be the home owners responsibility is to spray for weeds ( I guess this covers the tarmac contractor). Is roundup the best thing to spray gravel with before tarmac prep starts and tarmac goes down or is there something better to use to make sure these weeds don't break through tarmac. Most weeds are by the footpath and kerb where there is no traffic. Any suggestions welcome!

standardg60

Yep round Up, get the mix right (100ml to 5l) and spray on a dry day.

Fracking Cylon

https://www.boards.ie/discussion/comment/119212673#Comment_119212673

Thanks. Roundup is good on the rare occasions I've had to use it. Hopefully they're mostly surface weeds and the roots aren't too deep

runawaybishop

Any of the glyphosate based weedkillers will do the job. I haven't bought some in a while but Gallup has the same active ingredients as Roundup (360g/l of glyphosate) and was a lot cheaper.

Just hope for a dry day and put it out early or late so the sun doesn't evaporate it too fast.

RainInSummer

Are you thinking that round up will prevent seed from coming up? It only works on existing foliage. It has no residual effect.

If you just want to kill what's there then it'll work fine.

Also depends on the weeds. Some can actually pop up through the thicknesses laid on drives. I've seen it happen with horse tail (equisetum).

Oh and if you do use round up, don't use the premixed stuff on offer in garden centers and DIY places, it's diluted down enough to keep you coming back for more.

Dempo1

I'm just curious OP why the need to spray at all 🤔 surely the Tarmac contractor is going to insure area is level, Lay gravel, prepare & compact before laying tarmac or are they just going to pour tarmac over an unprepared surface 🤔

The preparation of the area before laying tarmac should surely deal with any weed growth in advance.

After tarmac properly laid and rolled its unlikely (not 100% Gaurenteed) that weeds could grow up through it, what will need to be done afterwards is mainta tarmac surface through occasional cleaning, minimising Moss growth and insuring it's not damaged by heavyoads etc.

Fracking Cylon

https://www.boards.ie/discussion/comment/119246907#Comment_119246907

The area has a big thickness of hardcore already in place, with crushed sandstone as a finished product rolled on top. This is what we are replacing, and where some weeds are growing. Contractor said we don't actually need to spray it, as the material he will be removing to prepare for tarmac should contain the roots etc, but it's safer to spary in my opinion, in case some residual root system remains. Tarmac won't be put down for a few months with wait times, but at least if I spray it now, it should kill exisitng growth, and spray again to kill off any new growth that will have come from new seeds.