Building with Hemp Part 1/2


society is concerned with global warming and carbon emissions buildings and building construction account for more than half of all co2 emissions if we are to reduce emissions we need to make buildings energy-efficient but we also need to use low energy methods of achieving this natural materials not only help to make buildings energy efficient but also they can make buildings healthier and function better natural materials generally have a much lower carbon footprint than conventional building materials most conventional materials consume a great deal of fossil fuel energy to produce and therefore contribute to co2 emissions we’ve been trying to find a method of building low carbon and energy-efficient simple and affordable that uses natural materials a hemp and lime mixed together seems to answer all of those needs as the technical construction was developed in France about 10 years ago and used to a small extent there but actually didn’t really take off for some reason we found out about the technology did our own research a number of people came together in the UK and we decided it was something that was commercially viable and it’s taken off to a large extent here there are probably about 50 hempcrete buildings all over the UK ranging from brewery warehouse 20 million pound projects down to individual houses and even people’s sort of summer houses in their garden I mean it’s been used for all sorts of different forms of construction while this building apart from the fact that it’s a small house that’s for my father to live in it’s a demonstration of this technique so that we can prove that it works we can show it to other people and to other architects other professionals and builders so that if you want to convince them of the technique they can actually come along and have a look at it and see it in the flesh it’s quite unique hasn’t been done before in Northern Ireland so this is us able to test both the processing and the complications of detailing on a building which is for ourselves the hemp research project was founded by Deborah to look into hemp which is a crop being used as a natural insulation but here cast with him this has led to a publication a book has just recently been published by ourselves and other co writers so this is quite timely that this building is now happening exactly at this point and in fact we’ll probably be reviewing some of the details that are in that book because very much have a hands-on understanding and fusing the material now we started the superstructure that’s the work above ground four months ago we start off with quite traditional footings a normal strict footing around the building and brought it up in block work up to subfloor level unavoidably using cement which you know how to do and be pragmatic about that and then we started the primary structure and what we decided to do is to start off actually with the principal the posts and the beams holding the roof structure to end up with a sheltered framework and that was followed by the stud work around the perimeter which is then being cast around with the hemp and lime the hemp needs a sort of rethinking in terms of what we call traditional building construction because we’ve been using a cavity block construction for the last century really and a lot of plastics in buildings so this is a monolithic construction and insulation properties of the hemp are both that it’s a good incident but also has thermal mass monolithic means that it’s one material right through it does have a stud wall buried in the middle of it but it isn’t layers of separate materials so even timber frame construction which is favored by a lot of people who trying to improve insulation has too many layers and too many different processes and that’s what we’re trying to reduce this is the primary structure carrying the roof low that’s douglas-fir locally soft and that was constructed the beginning of the process here you can see the tail end of the shattering which is yet to be removed and this section it has been taken away this is cast just a few days ago and still soft to the touch but firm you can see it’s solid enough this is the stud wall that’s sitting in the middle of that 300 thick line casting so that’s parent with some noggins cross noggins for stiffness and here we’re back to a sections not to finish being cast yet this is the base of the post here with a rigid fixing so we got rigidity in the whole building frame from the start sitting on its own pad stone and the subfloor level there below this is the radon barrier coming up tucked into the DPC and we have the electrics that we had to put this ducting in ahead of the hemp being cast here we have one of the electric sockets which we’ve cast into the wall because it wouldn’t be practical to try and chase this material so you’ve got to cast them in at the time and then here we’ve got the window reveal which is lined with the Herakles board which is permanent shutter and that would stay in place the main thing that architects want to know about this is how well does it work from a thermal point of view so a 300 millimeter thick wall like the one we’re building here will provide good enough insulation to meet part L of the building regulations depending on whether you’re in Northern Ireland or England




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