ABJ                      Thompson's Roof Seal

Thompson's Roof Seal is sold for waterproofing roofs.  However, I have found that it can be used for many other purposes.  The compound is a thin black water-based paste that cures by drying.  When fully cured the goo is totally waterproof.

A two and a half litre tin costs a bit under twenty pounds.  With the lid kept tight, the shelf life is extremely long, so it is worth buying at least half a litre, even if you only need a little to do a job.

Being a thin paste it will slop if applied in any quantity without support.  And if a dab falls on your clothes, it must be removed using copious water immediately.  I have a shirt sleeve cuff that is totally waterproof now, and very black, as a result of a dollop falling on me without my knowledge.  I'd know that shirt anywhere!

As I said it has a myriad of uses.  I'll list a few:

1    I wanted to fix a telephone cable to our rear outside wall of the housel, but the cement-spattered surface was immensely hard and would have been very difficult to drill for a conventional fixing.  Also due to its bubbly surface, the shingle in the cement mix would have been near impossible to drill.  Also a conventional fixing would have looked terrible.  So what did I do?  I ran the cable across the bubbly surface for about three feet.  I supported the cable by using bits of wood pole as a temporary support.  I then used a putty knife and smeared a small amount of goo between the wire and the wall making sure that both surfaces were wetted by the goo.  I waited for a couple of hours in warm weather with a slight wind.  By that time the goo had cured sufficiently to make a secure fixing.  I then did the next three feet in exactly the same way, and so on.

I did the same thing on the underside of a roof soffit, although it took more time getting the goo to bridge the cable to the asbestos surface.  It was here that I collected my black shirt sleeve.  Because the wall was painted white I had to paint the cable and the goo to make everything blend in.

2    The next job was waterproofing the gutter of our verandah where it had come adrift.  I made a fixing by drilling the gutter and the bracket and using a small nut and bolt.  I then proceeded to waterproof the leaks making sure I coated the  nut and bolt to prevent future rust.  As there was a quarter of an inch gap at one point, I smeared the the goo on to the two surfaces and then filled in the gap some more goo that I had loaded  with soft sand.  I mixed the sand and goo together until it was a black paste .  The sand and goo mix had enough self-support to bridge the gap.  When the paste had  cured, to make certain that there were no leaks, I painted everything with more goo.  The repair has lasted well over a year now and seems to be a permanent job.

The amount of goo used in each case is quite small, and half a litre will last a long while.  Just a few warnings.  If you leave the lid off the tin for a few minutes the goo starts to skin.  And the skin will not mix back into the uncured goo.  Do not use the stuff if rain is likely, as it will run and make a terrible mess.

3    You can use the goo to plug holes where insects might take refuge.  I used it to waterproof the edges of a piece of roofing felt where the wood was uneven.   I smeared the goo into the crevice as if it were a decorating filler.  Another place I filled was where an electric cable went though a hole in a switch-box.  I didn't want insects to take up home in the box.

Another warning.  Don't be fooled like I was into buying another type of bituminous compound.  I did this initially when I could not find Thompson's Roof seal.  The retailer told me that it was an equivalent, but this was not the case.  These may be good at what they are meant for, but Thompson's Roof seal is water-based, and cures by drying  --  like emulsion paint.  It is waterproof only after it has cured.

4    I used some of the Roof Seal to seal printer cartridges after I refilled them.  The uses are many.  But it is mucky stuff before it is cured.  I imagine it would break down with a spirit after the curing process had taken place, but I have never tried this.  But it doesn't rain paraffin or turps in this country!

I also have a tip on fixing thin flex-cable in the house.  Click on this link ABK