Thread: Tar painting for retaining walls

Personally I hate the black gooey stuff - Ormanoid but it is universally used for that situation. I find that it is too difficult to apply and you need to do two coats if you really want to be sure that there are no pin holes in it, even then......

There is a plethora of products out there and I haven't used all of them so I can't say what is THE best. Its a matter of personal preference so I am sure there will be plenty of opinions -

Watch This Space...........

Why? Only function I can think of is to keep groundwater from leaking to the outside. But this increases water pressure on the back of the wall, which is taboo in my book. In fact, we often deliberately place weep holes in the wall to augment drainage from the gravel filter layer to the buried drain pipe. Does your tar have some other function? Or is the retaining wall also a basement wall?

Joe - registered PE, Civil & Structural

Hi Joe, I would prefer to waterproof any masonry retaining wall even in outside situations to keep the face dry. Constant water promotes algae or just looks bad especially with a rendered wall.
You can still have weep holes or ag drains to relieve hydrostatic pressure.

Ah so. I keep thinking of Oz as lots of desert. Hadn't thought of algae, although I should have. My "white" stone chimney is almost green/black. Humidity, tree canopy, etc. On my list of things to do is a zinc chimney cap to leach zinc oxide as an algicide.

Thanks,
Joe

Ormanoid Brushable Duraseal,

coated 52square meteres of bessa block wall with it, brushed about 1 square meter, gave up & went and bought a cheap underbody (car) spray gun and 2l paint/thinners tin that fitted the gun.

The weather was a bit cool at the time, so I had to warm the 20l can on an old cooktop - pop the lid a bit first or "BOOM" . Then it only took about 4 hours to spray. The compressed air also drives the tar into all of those little holes and crevices.

My compressor is about a 22cfm job with a 200l tank running at 150psi (cutout) to 125psi (startup), pressure lower than this (125 to 100psi) was very slow going.

Interesting idea.
Did you have to thin the duraseal to get it throught the gun?

Tried thinning first before heating, this is what happened.

Mixed with some turps, which the manufacturer recommends for clean up, it took ages to blend with drill mixing attachment and then it seperated quickly in the spray pot, so no good.

I painted another wall 2 weeks later on a 30 degree day and sat the can in the sun for a couple of hours before I started and did not need to warm.

reminds me of the first and last time I used creosote. I sprayed that on. it was a stinker of a day 40deg and no breeze .
The creosote drifted in the air covering everything including a neighbours new white Falcon.
The bloke that was working with me ended up admitting himself into hospital and I spent a very painful night.

Mix Silasec with cement and water as per directions and paint on two coats. Much easier to use than ormonoid and works very well indeed.

Mick

Master Builders Technologies make a number of cement based waterproofing products that you may find easier and cleaner to apply than using bituminous products.

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