This is Old Lawns Farmhouse as you will never see it again. Today is the first day of what will be a lengthy project with an unknown ending!Having decided to stay put in our old Shropshire farmhouse for the foreseeable future, our thoughts then turned to what work should be done to secure and preserve it for the future. Like many old houses with solid walls Old Lawns Farmhouse (from now on known as OLF to save my typing fingers) was rendered with a thick coat of cement render, probably sometime in the 1960's. Intended as a means of weatherproofing, this cement based render in fact causes old houses like OLF to slowly degenerate by locking in the moisture which inevitable finds its way in via cracks in the render over the years. The walls of these old houses were intended to breath, absorbing moisture and allowing it to evaporate back into the atmosphere. The use of natural materials like lime plaster inside and lime mortars between the bricks and stones in the walls meant that this breathing could take place. Smothered by cement render on the outside and gypsum plaster on the indside, this breathing stops and the building starts to slowly suffocate. Any moisture finding its way into the wall from outside is trapped and has only one place to go - into the house, causing damp patches and helping to raise the internal humidity, resulting in condensation in the corners of rooms (low down near the floor), lifted internal plaster and flaking paintwork. Water vapour generated internally, by kitchens and bathrooms and people breathing(!) is also trapped inside the building and adds to the humid indoor climate.
You can read more about all these issues at www.heritage-house.org which was the place that eventually convinced us that we should take action to save OLF. Following a visit by Pete Ward of Heritage House Ltd in early October 2012, we decided that the first step in renovating OLF will be the removal of the external cement render on the ENTIRE house. Depending on the condition of the brickwork and stonework underneath we will then decide what to do next. There are a few options:
- Clean the brick surfaces and repoint with lime mortar. Possibly paint the re-pointed brickwork with a breathable clay based paint if the decorative appearance is not too attractive.
- Repoint with lime mortar and re-render but this time using lime render which will allow the walls to breathe.
- Apply a breathable external insulation layer and re-render on top of that with lime render.
These options get progressively more expensive but the decision of which route to take will mainly be made based on the cosmetic and structural condition of the brick/stonework once it is revealed. Which takes us to the second post in this blog - what lies beneath!!?