Fixing a roof leak with lead soakers

I got an awful feeling of dread when I recently looked up at the upstairs corridor ceiling  of our Victorian cottage to see a dark grey damp patch forming in one corner. We had a leak.

Our cottage was originally two cottages, and the leak was coming from somewhere up on the roof, around the parapet wall between the roofs of the two cottages (below). Most of the roof dates back over 100 years, and is not felted under the tiles, so this sort of thing is something I always dread.

The leaking roof – shown with the old lead flashing stripped off

So as with all leaks I set about looking for the cause. The roof was luckily easy to reach, as a central valley runs the length of the (now one) cottage, and it was into this central valley and the ceiling below that the water was leaking.

I thought back to a leak I had in a similar cottage I lived in down in south east London several years previously.

The roofer I found back then had told me that the leak was partly due to water sinking down through old mortar between the bricks on the parapet wall (“we have a lot more rain today than the buildings were designed for back then” he said), so he installed coping stones on top of the parapet wall and that seemed to fix the problem.

I had some old tiles lying about (it’s amazing the stuff that the previous owners left behind – these were half buried under a tree at the top of the garden!), so I covered the parapet wall with these and also put a new render bead on the course of bricks that protruded out from the sides of the parapet wall (above left).

The next bout of rain arrived and the damp patch on the ceiling got bigger, so it was back to the drawing board.

The next thing I did was spread polythene across the lead valley directly above the damp area, tucking it under the roof tiles on both sides – to see if the lead valley was the cause. No it wasn’t, and the damp patch got larger.

So now I knew the roof itself was to blame, and a bit of digging around in the roof confirmed this – water was dripping down the bricks of the parapet wall inside the roof. Before you start wondering, I hadn’t immediately thought this was the cause as there was a huge piece of lead flashing running down the roof, rendered into the parapet roof.

I tried to call the roofers who had done a bit of repair work when I bought the cottage, but I couldn’t get them to return my calls, and with money tight as ever, I decided I would have to fix it myself.

The first thing I did was to research on Google to find the the methods of butting tiles up to a parapet wall or chimney so as to make them watertight.

Different ways to butt tiles up to a parapet wall or chimney

I’d seen the roofers previously repair another roof at the cottage with lead soakers, so I thought I’d give this a go.

i) Because it seemed a little less complicated than creating step flashings

and ii) because I figured I’d need to render the wall afterwards anyway (which I think you probably need to do to prevent rain water getting in between the parapet wall brickwork and the top of the lead soaker.

A roll of 240x3000mm lead flashing set me back over £45!

So I needed to buy a roll of lead, and some new tiles, as the tiles under the lead flashing were broken and disintegrating.

Buying the lead was the easy bit (picked up from a local builder’s merchants), but at over £40 I was a little horrified at the price!

 I decided to buy the tiles directly from the manufacturer as Dreadnought tiles were reasonably near by and I was able to buy 100 or so (with some tile-and-a-half-tiles to create the staggering effect) machine made clay tiles and pick them up on my way back from a work trip in London. The tiles were another £150 or so, and I’ve since found out I could have saved a bit of money by buying recycled tiles, so do a bit of Google-ing if you find yourself in a similar position!

Spare rooms

So on the next available sunny day (few and far between recently) I flung a few dust sheets and blankets on top of the lead valley to protect it and set about stripping off the old tiles.

Once these were gone, the next job was to repair the wooden roof battens that had either gone rotten due to the leak, or just disintegrated with age. I cut some strips of treated wood I had left over from a fence repair to the right size and screwed these in place. If you have to do something similar you can find battens in any good DIY store (Wickes, B&Q etc).

Then it was back down the ladder to make the lead soakers, which I did by rolling out the lead flat, and then following the dimensions I had seen in the diagram (above) on the internet, I marked out and cut the lead with a stanley knife, and then bent it round a plank to the required shape.

I was pretty pleased with the end result!

The next stage was the really satisfying bit of laying the new tiles, interspersed with my new lead soakers.

Whilst laying the tiles and the soakers was straight forward, the difficulty came in linking these into the existing roof, as the new Dreadnought tiles were hard as granite, and difficult to cut with my rather small angle grinder.

The important thing was to ensure that there was a decent overlap as the old and new tiles dovetailed into each other up the roof.

Where possible I inserted new tiles and trimmed the old ones down with my Bosch4-1/2″ angle grinder as these were much softer to cut than the new Dreadnought tiles.

With the tiling finally complete all that remained was to tidy up the old stepped lead flashing at the top of the roof around the chimney

With only a couple of hours of daylight left, I hastily prepared a sand and cement render mix (4 parts sand to 1 part cement with waterproof PVA waterproof the render and make it easier to work with) in my wheel barrow, mixing it up with a spade, and troweled it onto the parapet wall.

The tiling is complete and the parapet wall rendered.

It wasn’t due to rain that evening but the temperature was lower than I would have liked to apply render in, so I covered the parapet wall in an old sofa throw to protect it from any frost during the night.

The job was complete, the roof water tight, and the leak fixed, and more importantly, with an old roof that doesn’t have the added protection of roofing felt, regular maintenance is very important and I now know how to do it myself. Bring on the next DIY project!