Hot tar crack filler

[Huge]

My house is a conversion of a cow barn, as a result of which I have a very large concrete yard made up of about 30 sections, each about

3 metres square. The joints between them are full of weeds. I'd like to fill the joints, and have just experimentally raked out the weeds and washed the soil out around one section, which turned out to be pretty straight-forward.

How difficult is it to use hot tar to fill these joints? And if not that, what else could I fill them with? The concrete is pretty ratty, so the joints are very variable, and there's a lot of it, so (e.g.) patio grout is out of the question.

[Mark Allread]

What about a dry mix brushed in, tamped down and topped up?

Hot tar is possible but can be messy (as well as smelly and dangerous if spilt on you) and you would end up with quite a colourful yard as the black would contrast nicely with the concrete.

Think Holstein or Zebra :)

[Capitol]

IME dry mix breaks up after a few years. Wet 3:1 mix lasts. Add some PVA and weedliller in the mix.

[alan_m]

The gangs tarring the joins in concrete roads seem to use a metal watering can (without rose) to pour the tar into the gaps.

[Nightjar]

They are expansion joints, so they need to be filled with something flexible.

[Huge]

It has to be flexible - these are expansion joints.

I've found this stuff, which might do;

Bit expensive, though.

We're talking 50 or 60 y/o concrete that's been extensively, um, "treated" by cows. It ain't white. it ain't even grey.

:o)

[Huge]

That's what I was thinking.

[alan_m]

I see that some companies producing metal cans differentiate between a watering can and a dedicated tar can. A watering can may be just soldered whereas a tar can may be constructed differently so it can be placed on a burner ???

[tabbypurr]

Easier to just use bitumen in solvent, ie bitumen paint. It doesn't look as bad as you might imagine, fwiw.

NT

[Huge]

I should, of course, have looked here first;

[news]

I've used asphalt to reseal some roof seams and I just broke (it breaks like glass with a hammer when cold) pieces off the asphalt block and melted them with a propane torch into an old motor oil jug to pour. I still have the remains of the block but they must be cheap enough from any roofing store.

I have also seen a vat of hot asphalt catch fire when the burners were left on too long, they put it out by shutting the lid but it smoked incredibly for a long while after.

AJH

[Bill Wright]

I did mine with hot tar. It's pretty easy and it does a right good job. You buy it in blocks. You need a really good fast gas ring. it's worth hiring the proper thing. Put a wind screen around three sides of it; that makes it hot the tar up a lot faster. Get the tar really really hot; not just runny, really really hot. Pour in it with a metal watering can with no rose. Maybe squeeze the nozzle in the vice to get a V shape. Wear goggles. Don't pour onto water. Choose a day when the sun's been on the concrete for a few hours. It doesn't matter if it splashes on the concrete a bit; you can get it off easy once it's gone really hard. Do that job a day or two later. For the preliminary raking out make a tool with a prong the right width for the gaps between the concrete.

Bill

[Harry Bloomfield]

alan_m has brought this to us :

I have an expansion joint in my concrete drive. That originally had a wood strip in it, intended to rot and now filled with soil / weeds. I have a pile of scrap roofing felt, which I had in mind to melt up in a pot to clean out and fill the joint.

[Thomas Prufer]

An alternative is a dry mix of (a little) hydraulic lime and kiln-dried quartz sand.

Rake out joints, brush in the dry mix with a broom. The mix settles into the joints well because it's dry, like sand in and hourglass, and eventually sets with ambient moisture. Is's not very hard, more like sand fixed into place, so it may work on the expansion joints. Weeds don't have much of a chance, but the stuff I see has narrow joints.

It'll be a whole lot cheaper and a lot less work than pouring tar -- but may not be the result you want.

Thomas Prufer

[Martin Brown]

Lime based mortar or coarse grit sand. It needs to be something that has a bit of give in it. Hot tar will be messy, black and get everywhere unless you have a very steady hand.

[PeterC]

If the tar is much more than the width of the gap - or if it's a wide gap - sprinkle som sand on it. It's very slippery when wet.

[Nightjar]

On 09-Aug-17 1:59 AM, Bill Wright wrote: ...

Isn't that a job for a really big angle grinder?

[Huge]

The concrete is likely over 50 years old, and the gaps are very variable.

Scraping the weeds out with a hoe and washing the soil out with a hose worked well enough. It's filling the gaps that's an issue.

[news]

It's flexible within limits, it just breaks off the block like knapping a flint

AJH

[Huge]

It's a supercooled liquid.