Render unto the pond
Now we have chalked up another wet weather record (the wettest summer for 100 years) the rain seems to be resting on its laurels and we have a fairly dry week coming up. Today I decided it was time to tackle the shallow pond. The problem is that the water leaks out of the pond at the join between the mortar (or render – I am not sure of the difference) and the liner, whereas I want the pond to be able to fill up right to the top. The mortar has been applied in a slope, which means that the join between the mortar and the liner is very thin, and it’s also quite ragged, so it would be difficult to apply a bead of pond sealant compound, which is what I want to do.
Original mortar, with ragged edge
So I chiselled off the thin edge of the mortar, roughened the rest of the mortar up with lots of scratches from the chisel, and then mixed up some new compound to make a vertical edge that would form a better junction with the pond liner.
Mixing mortar is not something I have ever attempted before, but I have iced plenty of cakes, and I read the books and did my best. I mixed it in an old washing up bowl, and I used 1 litre of cement to 4 litres of sand. At least one of my books said that sharp sand was better than building sand, but I think that was wrong in this case, because sharp sand has lots of big bits of grit in it, whereas I think it needed to be smooth. I then realised to my horror that I had probably made far too much. Unlike cake icing, you can’t just put the excess in the fridge and eat it later with a teaspoon.
I was careful not to make the beginner’s mistake of putting too much water in the mixture, but I may have made the slightly more advanced mistake of not putting enough water in it. I don’t know what happens if it hasn’t got enough water in it, but it may not be very good. I kept wetting the old mortar as I applied the new and it probably ended up wet enough in the end. And I was pleased to find that although I had made a little too much, there was not a lot left over. I made it into a little square patty and left it to bake on the tarpaulin so I can then use it for hardcore for laying my stepping stones. Then I washed everything out and poured the washings onto the tarpaulin, where the water can evaporate over the next week, and then I can sweep the dust up and dispose of it.
I can’t pretend that the end result is going to look pretty.
My new mortar patched onto the old
However, I just want the pond not to leak at the moment. If I achieve that, I will stick lots of cobbles around the edge of the pond and they will hide most of the mortar. My cunning plan is to glue the cobbles that are further away from the edge to the liner, but not the ones that are right up against the edge. Then the cobbles further down the liner will stop the top ones rolling down to the bottom, but I can remove them if I need to make any more repairs to the mortar or the watertight seal.
So the plan is now to wait a few days, and then check to see if there are any bits that need improving, and make a small amount of mortar to mend them with if necessary, and then wait a few weeks for the concrete to cure, and then paint it with Pondseal.
And then I iced a cake. Much easier.
Chocolate cake, iced using knife, not pointing trowel