Learning from Passivhaus Building

The people of Green Building Store (UK) have generously produced and published a freely available online movie about some of the challenges they faced in a Passivhaus construction project in the UK. Though I am wary of taking on the Passivhaus standard as is (reservations I’ve written about in posts about Passivehaus and Rural Studio) I am also trying to be careful not to pour the baby out with the water. There is a lot of common sense in Passivhaus and much of it is excellently communicated in this movie. You can view all the parts here or possibly start with this embedded video and then continue to each consequent part:

So, with much curiosity and interest I watched the movie (reviewing some of the chapters numerous times) and made some notes of things that I hope to incorporate into our building process. This list does not include the core-issues of Passivhaus construction (insulation, minimal thermal bridging, air-tightness, ventilation and passive solar gain) which deserve careful context and consideration – especially when it comes to hemp-lime construction which introduces unique qualities to both the construction process and the resulting structure.

Design & Details

It is invaluable to spend time designing and paying attention to details before the actual construction process. Construction is an established process and skill which carries with it a taken-for-granted attitude. Professionals have a way of doing things and will prefer to do things the way they’re used to doing them – which may lead to cutting corners in design and to on-site improvisation.

This can be destructive in a project where new standards of building, new materials and new techniques are involved. Taking the time to plan things in advance, to drawing diagrams & making calculations creates a thoughtful path towards a desirable result. Of course it is inevitable that unforeseen challenges will arise during construction and that some changes and improvisation will be required – in which case a plan gives some indication of how far you’ve deviated and what you need to do to get back on track.

Special attention should be given to details. I’ve been working on a wall-to-floor detail for weeks – compiling all the information and knowledge I have come across, reconsidering it in the context of hemp-construction, our house design, minimizing costs, minimizing the use of concrete and relying on locally available materials. There is no ready-made template for what we are doing, there are many options to choose from, there are many considerationt to incorporate. We could take the easy path and hire foundation contractors and let them do their thing – but that would lead away from the kind of warm, pleasant, ecological and efficient house we hope to live in and bring us to the standard cold and humid house that contractors have been building in Romania for may years.

Team Work

A typical construction process tends isolate and compartmentalize knowledge and skills. We would consult with an architect to design our house. Then we would pass the plans to an structural engineer who would need to figure out how to support our house. Then we would pass the architectural and structural engineering plans to a heating engineer who will try to provide an adequate heating solution within the existing constraints.

This kind of approach can lead to an inefficient process and an inefficient house. A good engineer can provide a structural solution to meet almost any need – but at what price? How much extra work, materials, construction effort and waste may be required to implement the engineered solution? Similarly a heating engineer can theoretically heat any space – the question is how expensive and complicated will the system be and how much energy will it consume? This is a brute force approach.

We are trying to put together a team that will work together during all phases of the project. We’d like everyone to be there to provide input at every stage of the project. We’d like the architect to provide input on choosing good land and on siting of the house on it. We’d like the structural engineer to make suggestions on architectural decisions that may lead to simpler and more efficient construction using less materials. We’d like a heating-engineer to review the size of our spaces and to make suggestion that may improve the energy-efficiency of the house.

It takes integrated and out-of-the-box thinking to create the kind of integration that leads to a house that facilitates an “eco” existence.

Opening Details

I have been wondering about how to go about properly insulating openinsg like windows and doors. The movie offered some very useful tips about these issues and these are the ones I noted:

  • Windows should be placed at the center (depth) of the wall.
  • Windows should open inwards – placing the thicker part of the frame on the outside for better insulation.
  • Special sealing tape (such as Pro Clima Contega FC) should be applied between the rough structural opening and the internal wall and then covered by the the internal render.
  • Special sealing tape (such as Pro Clima Tescon) should be applied between the window frame and the rough structural openings.
  • A concrete slab should not extend to the door opening to prevent heat loss through it.
  • The door opening slab requires an insulated and weather resistant material (such as fiberglass).

A big thank you to the people at Green Building Company. This movie has been very educative and helpful.

Learning to Read Plans

I’ve been spending the last few weeks immersed in reading about wood-framing. I’m really enjoying the experience of feeling that it really is possible to self-build a home. It’s logical, straightforward and building with hemp simplifies it even more.

I recently came across these sample PDF plans of an eco-house from Studs – a UK timber frame design company. I am happy to say that it isn’t all giberish to me anymore 🙂 I still can’t read it all – and some parts are a bit overwhelming – but I think it’s good practice to start looking at such plans. They provide house design ideas, they teach structural lessons and they prepare you to communicate with other professional which we expect to be doing.

Modece Architects

It’s been over a week that I’ve had the website for Modece Architects open in my browser. I really enjoyed the website – it feels like an authentically green site – one that actually walks the walk. Particularly I’ve browsed back and forth endlessly in the sustainable-construction gallery which has been quite an eye opener. For example …

This image hints at the potential of using quality timber framing together with hemp construction – which I was just wondering about…

or this image that demonstrates that loose hemp!!! can be used in floor insulation:

… or this image of a do-it-yourself solar panel:

… honestly, every picture in their gallery is like a magical doorway into knowledge.

But what really tickled my fancy was that as I was revisiting that must read book on hemp-lime construction I recommended a while back – I made the connection that the hand-drawn illustrations starting on page 31 were contributed by Ralph Carpenter of Modece Architects … and I am thinking “yeah, that’s the website I’ve got open in my browser” … so it seems that the world of hemp-lime construction is still a nice and intimate community 🙂 Great fun!!!