Over the years the harsh winters had led to water getting under the stone roof; causing leaks and timber rot. We had tried a number of fixes over the years, but in 2015 decided the time had come to stop tinkering and get to the root of the problem. Aside from old age, the biggest problem was the absence of a waterproof membrane under the stone roof to ensure any driven rain is kept out.
We appointed a local company, David McNulty Construction, to do the work in September 2015. Before they could start, we needed a forecast of 10 days of good weather. This was the period needed to lift off the stone roof flags, replace the timber frame and put in place a waterproof membrane. After the membrane was down, the Cottages would be watertight and the refitting of the stone flags could progress as the weather allowed.
After weather delay after weather delay, the 10-day window appeared on 18 April 2016. This was cutting it fine. It was almost the last date in our plan if we wanted to get the work completed before our first 2016 guests arrived.
There are more than a few challenges with the project:
· The site access meant that the fork lift could only get to one end of the scaffolding; so everything had to be manhandled along the walkway;
· That’s fine, except the stone flags are huge and heavy. There are roughly 800 flags and each weighs around 25kg (and some a lot, lot more). What you see on the roof is only around one-third of the flag’s height;
· Lastly, when the cottages were built no one much bothered with levels or right angles. So cutting the new roof timbers was a custom job, and deciding on reference points for level was as much art as science.
The stone flags are hung on batons that run across the timbers; with each flag having two notches cut out for the nails to hold them in place. Although, given the weight of the flags and the fairly shallow pitch, gravity is doing most of the work of holding the flags in place). The old iron nails were heavily rusted and showed an interesting variety; some long, some short, some thick, some thin, others looking remarkably like those used to shoe horses. We have kept a few as examples.
Stripping off the old roof was a filthy, dirty job; a 120 or more years of dust, mortar and the detritus that ended up wedged between and under the flags. Each flag needed to be lifted clear of its nail hangers, then slid down over the flags below, eased on to the scaffolding and then manhandled to the end of the walkway onto the waiting pallet wedged on the end of a fork lift…. 800 times.
Given the age of the building, it was too risky to remove the existing roof timbers (who knows to what extent the walls were being braced by these timbers). So we created a new timber frame “over” the old one and then secured it in place with a concrete ring beam around the top of the walls. Once the new timbers were in place we covered the roof with a “breathable” membrane liner (Dupont Tyvek). This was then held in place by new batons. Once the Tyvek membrane was in place the Cottages returned to being watertight. Thankfully, the weather held good for the project (good in “facing The Atlantic” terms).
Once the Cottages were watertight we could reverse the stone flags removal process; use the fork lift to bring back the pallets to the scaffolding and then manhandle the flags down the walkway to the bottom of the roof and then drag the flags up the roof, hammer nails into the baton at its hanger “notches”. And repeat, 800 times over for three weeks.
There are two schools of thought about the removal and replacement of the flags. One says you number each flag as it comes off, so it can go back in the same place. The other says that you just group the flags by size (each row is a different size – largest at the bottom... luckily).
The “grouping” approach (which we used) says that you will never get everything back where it came from. Some flags will have been broken, some will have become weakened, and variations in the pitch of the new roof will mean flags will need cutting anyway. So this school of thought says, don’t waste time, just offer up the roughly right size flag and cut as required.
We had expected to lose around a quarter to a third of the flags; over time they become brittle, they get broken in the manhandling, now and again one gets dropped. In our case, because of the quality of the flags, we only lost around 10%. We were able to source “spares” from a nearby Cottage that had gone for a modern tile when renovating the roof.
Once the roof was on there was a final job; fit new guttering and
The guttering was the most fun of the whole project. The builder has a machine to extrude seamless aluminium guttering; just pick your length. We had an extrusion that was the length of the two cottages (so no joins to leak), That is 20 meters. Aluminium is quite malleable. So you end up with a 20 meter snake you need to somehow walk around the building.
Despite our worst fears (actually, realistic expectations) we didn’t lose a single day due to the weather. From start to finish, it took five weeks to complete the roof project. The builder did a great job, on time and on budget. And, we all remained friends too.
We are really pleased with the result, we hope you are too. There is a photo album that records the project from start to finish.