Keeping Stone Dry, a French Drain on pre-1919 Scottish House Esk Tower

Here is a Twitter thread I made in February 2021 about keep the stone on our house dry by digging a French drain. I don’t want to be locked into Twitter so I’m re-posting it here to keep it alive.

See also Esk Tower – Retrofit Insulating a pre-1919 Scottish Stone Built House video (YouTube) and Insulating a pre-1919 stone built Scottish House, Esk Tower blog.

This is my home. Esk Tower. Built as.a pumping house it’s now my house. Every new owner has added a new layer around the outside to make the grounds look more pretty. This is a story about a French drain we dug.
It has its own culvert which probably used to keep the pumping engines cool. It’s how water should be around a building, all channeled and not likely to affect the stone.
As the pandemic spread last march I was high above the world repainting the dormer windows looking down on the ground below pondering what was under it and how the stone was keeping.
So one day with nothing much to do except stay at home we took an SDS drill, pick axe and many shovels and dig around a corner. Layers of ornamental stones and plastic sheeting gave way to layer of brick, coal and finally clay. It was hard work.but the stone could breath again.
The next weekend we tried another corner, this was cemented in so the sds drill came out. It hardly touched it.
Fortunately we had got a Titan stone cutting circular saw with blades the size of dinner plates there is no arguing with this.
Having dug up the cement the stone could breath for the first time in a century and get a good wash down.
Then it needs lots of repointing. Using breathable lime from masons mortars or course, not the cement people in recent decades have used, that just traps in moisture damaging the stone.
I spent a weekend drilling under the doorway, full of rubble, glass and a frog under there.
All of which produces lots of waste, beware of telephone wires when stacking skips three high.
Ah now this corner was tricky, a clay sewage pipe from the neighbouring house, cracked of course so not surprising our stone was reading as more damp than you can burn firewood at. Emergency drains people came out and replaced the pipe.
Ease up ment we could get in help and we got the trench along the front of the house. I’d been wondering how the down pipes connected, it turns out the didn’t.
With the digging near the building done by hand we could hire a digger for the rest, this is a lot more fun than doing it by hand
Alas there a lot of utilities and a digger makes easy work of water pipes. And electric cables. And gas pipes.
There followed a panicked night of young men in yellow jackets and the following day digging in mud to find where water needed reconnecting and make sure electric was ok. This was very much type 2 fun. Maybe type 3.
At last we could replace the rest of the clay sewer and put in the French drain pipe to help water drain away from the walls.
Then make a bund of earth on the right and cover that in fabric to drain more water away from the building. Then connect up the rain water pipes from the roof. lots of measuring and cutting needed here.
Finally fill in above the new drain with pebbles and sort out all the dug up earth to remove stones and lay that back down ready for grass in the new year
And the random hole we cleared out earlier and in years past was a stair case we put a roof on and made into a wood store.
And that is the story of how we made the tower stay strong and dry, with lots of digging and lime and French drains and utilities all over the place.