The SPAB (The Society for the Protection of Ancient Buildings) is Britain’s much respected oldest building conservation charity , founded by William Morris in 1877. I’m a member of SPAB along with 8,500 members, membership starts at £47.00 become a member here.
Tutors for the day
Douglas Kent (SPAB Technical and Research Director)
Anthony Goode (Conservation builder)
Dr Joe Bispham (Carpenter, joiner and historic building consultant)
This course presented by the SPAB is aimed at those working on traditional buildings. These are defined as solid-walled properties pre-dating about 1919 – no less than 20% of the country’s housing stock. Traditional buildings differ fundamentally in their construction from modern ones and this necessitates the use of alternative repair strategies. Many traditionally constructed buildings are also listed or in conservation areas, which brings additional requirements. The well-meaning but misguided application of standard modern approaches to traditional buildings can be ineffective, damaging and unnecessarily costly.
The first part was presented by Douglas Kent.
It covered all of the below
Traditional buildings (1919), solid walls, lime-earth based mortar, shallow foundations
Moisture control, damp diagnosis, comparing modern and traditional buildings and how they deal with dampness
Controlling dampness, using french drains, lowering ground levels, removing plastic external paints and hard cement bridging renders to allow evaporation. Careful use of lime plaster internally where there isn’t a salt problem.Structural flexibility
Typical defects and types of repairs, typically timber frames
Listed building consent, Town and Country planning act 1947, 1990, justification needed for demolition works from 1968. 500,000 listed buildings, all pre 1700 are listed, 3 different grades, 2.5% Grade 1, 5.5% Grade 2 *, the rest are Grade 2 . The listing protects the entire building, not just the outside. Some buildings can be de-listed subject to an appeal.
Conservation areas, 15,000.00, restrictions can be to trees, satellite dishes, dormers, and article 4 being more strict with windows.
The conclusion of this is that this is a helpful framework rather than dogmatic rules.
Building limes was presented by Anthony Goode.
We discussed all the different types of limes from, lime putty, hydraulic limes, and NHL.
limestone how it is used to make lime, where it’s from, and what and where it can be used in a building.
Roman lime concrete, and how it was used in marine works.
Pozzolanic (crushed brick/tiles etc) how this can be used to speed up the process.
Great discussion on Natural Hydraulic Lime (NHL) and types NHL 2, NHL 3.5, NHL 5, the higher number being the stronger and faster the setter. Interesting thoughts on the strength of NHL 3.5 and that most people think that a 3-1 mix is still soft compared to a lime putty, and it isn’t.
Hot mixes, when they were used and how, and why there is more of it being used today, and is the new hot topic with lime .
Finishing off with lime wash, how to colour, how to test, drying times between coats
Anthony Goode also carried out a practical session in the afternoon when the groups were split into two.
Below Douglas Kent and Anthony Goode below making a lime hot mix
The hot mix produced
Different lime pointing tools for different bricks,stones, many of these are homemade
Timber repairs was presented by Joe Bispham.
Pictures of trees illustrating different parts of the tree and how there used in a building.
How in mediaeval times they managed woodland of coppiced and pollarded timber.
Legal requirement of managing woodland in the time of Henry the V111.
Different types of timber repairs, with excellent case studies showing how repairs were carried out properly and repairs that have been carried out the wrong way resulting in bulging and rot problems. Where and how to use a physical damp proof course.
Tips on working with timber and where to cut and how to prevent problems when working with green oak.
Using wood at the correct moisture content reduces swelling and shrinkage to a minimum.
The lower the moisture content the greater the strength. Wood will not decay if its moisture content is less than 20%.
Treatment of wood by preservatives, varnishes, paints, water repellents, and preservative stains are more effective when carried out at the correct moisture content.
The trade of softwood and hardwood timbers from Northern Europe.
Large amounts of softwood timber exported England from Baltic Ports of Rega and Memel throughout the 18th Century for construction and joinery.
Samples of timber demonstrating a section of timber, growth and dendrology, and typical rotten timber frame timbers.
I thought the course was excellent, although I regularly specify and work with lime plaster, render and lime pointing I still learnt some great tips. Also I gained some great tips on timber framing repairs which we regularly need to carry out in the Wiltshire area especially around my local villages, along with knowledge gained from the case studies. Douglas also explained brilliantly about traditional and listed buildings that topped up my knowledge.
I had my name down before the course had been finalised with SPAB, and I know many people will be looking forward to the next one as everybody really enjoyed it and took a lot away with them, along with the great handouts 🙂
Thanks to everybody involved at the PCA and SPAB for putting this course together.