Natural Building: Round Timber Frame Construction with Ty Pren
Posted by Celtic Sustainables on 19th Jul 2019
Over the last few months we have been excited to see a roundwood timber frame building being constructed in Cardigan. You see, our local Community Forest Garden is relocating. Having outgrown (sorry for the pun) it’s original site in St Dogmaels, Alpay and his team of volunteers for Naturewise are starting afresh just along the road from our shop.
Tŷ Pren, a worker’s cooperative specialising in sustainable eco buildings and structures using natural roundwood timber, have been building the new Forest Garden Community Hub and training lots of volunteers along the way.
Using locally sourced materials where possible Tŷ Pren (pronounced Tee Pren and Welsh for Wooden House) have been steadily constructing the Hub building since March this year. It has been a swift build that could only have finished earlier if Jamie and his team hadn’t scheduled in time to demonstrate round wood timber framing at Glastonbury 2019!
Building with round timbers is an art. However it’s an ancient natural building technique and therefore the basics can be learnt quickly. Building with round timbers requires relatively few tools and the building materials can be sourced locally it makes for a very sustainable project. Perfect for a low-impact build.
The build has been photo-documented on the Tŷ Pren Facebook page. However in summary the round timber frame construction (before the wattle and daub walls are finished) looked like this:
- Stone pads for the vertical round wood timbers carefully positioned on a level site.
- Roundwood timber frame constructed (see also image above)
- Base stone wall created
- Level horizontal sawn timber lower wall edge and window areas constructed
- Lathes woven between frames to hold the wattle and daub wall finish (note different lathe materials used particularly the woven hazel beyond the window).
The design of the round timber building also includes (not shown in the photo right):
- A central raised central roof area to allow for natural light into to the building
- A green roof
- Rainwater Harvesting from the green roof to water butts.
After the walls had been infilled with wattle and daub made from clay from a local aggregate supplier – MD Recycling - the Tŷ Pren team and client Naturewise decided to finish the walls with lime wash.
This is where Celtic Sustainables came in as we supply great lime products including pigments for lime wash.
How to make Lime Wash
Initially we suggested that, as the Tŷ Pren team were new to lime washing, they follow our basic lime wash guide using Lime Putty and dry pigments suitable for lime. This is a “cold” lime wash technique that is relatively safe as long as you are wearing the necessary safety equipment (mask, gloves and safety goggles). However it does require more coats of lime wash than “hot” lime wash to achieve the same opacity of colour.
As luck would have it, just as Jamie and his team of volunteers were starting this stage of the build, Jason Bushnell from Pembrokeshire Limework was back and forth from our shop for supplies for a project. Jason was more than happy to pay-it-forward by giving Tŷ Pren an impromptu on-site hot lime demonstration whilst discussing the various pros and cons of the two techniques. Quicklime (hot-lime) is a highly reactive material which is dangerous if not handled correctly so we were pleased that Jason gave expert first hand advice and training on its use (we recommend that anyone considering using hot-lime is trained, aware of the risks and correct safety precautions and personal protection equipment before ordering).
Tŷ Pren carefully continued with the hot lime wash technique using Calbux Quicklime. They added Yellow Iron Oxide and Indian Red pigments to create the yellow lime wash on the outside of the building and the red lime wash on one internal wall. The white internal walls were achieved by simply with using lime wash without any pigments.
Jamie from Tŷ Pren told us
“Using lime is not so daunting as first thought. With the proper personal protection in place its use and application is relatively simple and satisfying to apply.”
Photos show: wall being wetted down before applying the lime wash (top), beginning to lime wash (middle), the finished interior lime washed walls (bottom).
Up until this project Tŷ Pren have designed and constructed round timber buildings letting customers add colour and finishes as they desire. Now that they have had an opportunity to make and apply lime wash using different techniques, is it something they will add to their offer?
“The use of natural cob and lime render is something I want to explore more in the buildings I design. Lime washing gives me a design element that not only enhances and protects, but allows the buildings I create to breathe. “
“The team at Celtic Sustainables in Cardigan were extremely helpful and knowledgeable. Their assistance in the choice of lime renders and washes, and their connections with professionals within the industry, were a great support in the construction of the Cardigan Naturewise roundhouse“.
Jamie, Tŷ Pren
We think the Roundwood timber frame building looks simply beautiful with its lime wash finish. We can’t wait for the forest garden to be planted up around it
If you would like to visit the roundhouse that Tŷ Pren built at the Cardigan Forest Garden, please do check the Naturewise website first for open days and volunteering sessions (as the site is locked when not in use). Alternatively you can ask for details of the next Forest Garden events at the EcoShop in Cardigan (profits from the shop help fund the Forest Garden).
Check out the Tŷ Pren website and facebook page to find out more about Roundwood timber framing projects and their development of traditional re-emerging skills.
And of course if you are ever in need of lime wash putty or pigments for lime we have a great selection here at Celtic Sustainables and can ship all over the UK.