Inspiration for my next home improvement project, British Sign Language energy saving resources. Jon, this is really a fantastic article and a great help to a novice DIYer looking to tackle a 1920s house with very poor insulation, so thank you. I had insulation put under the suspended timbers of three rooms in July. Ive now got to the bay window at the front of the house and have discovered that the air bricks are exactly level with the joists. Send us a message and one of the team will get back to you as soon as we can*: Data Protection: The information you provide on this form will be used by the Centre for Sustainable Energy to contact you in order to give you impartial energy advice. Ideal Home is part of Future plc, an international media group and leading digital publisher. This is a very useful article as thinking about doing this in our house. To achieve this standard, the Energy Saving Trust advises installing at least 70mm of high-performance foam insulation, or 150mm of mineral wool. Save my name, email, and website in this browser for the next time I comment. However, you should consider insulating any floors that are above unheated spaces, such as garages, as you could be losing a lot of heat through those. I would like to screw few metal brackets to the walls supporting joists and place PIR board on them. Kind regards This ensures your home is protected as much as possible. Do we need to install a fan in addition to move the air around. It does create its own challenges in terms of handling and fixing. Youll also have to find out which floor type you have; older houses tend to have elevated flooring (floorboards fitted across joists with a crawlspace beneath), whereas newer builds typically have a solid concrete floor. Remember to put a net and staple it to hold it nicely. Laying a laminate floor in a room can cut out many of the draughts but it will not dramatically reduce heat conduction and it can be a real shame to cover up some splendid wooden floors found in older properties. Many older houses with suspended timber floors have big draughts and inadequate floor insulation; this can cause cold feet as well as higher energy bills. It is cheap but not as good an insulator as PIR thermal insulation board and is a pain to cut to the right size. Hi Izzie, If you dont feel confident lifting your floorboards yourself, you can get a professional to do this as well as fit the insulation and replace the boards afterwards. Unlike the floor joists it is not a structural element (not load bearing) and it would not be considered a potential source of ignition. With any luck, your home will have a cellar or hatch so you can see the underside of the floor, but if not, you may have to lift up a corner of the carpet and underlay. Solid floors are normally insulated above the top concrete or screed (a mix of sand and cement) layer using rigid insulation foam. Happy under floor insulation amateur :) says. Fibre glass and rockwool can be great for floor insulation when used with a membrane to prevent air flow, See the diagrams above for how either a vapour control layer or a breathable membrane can be used. The benefit of using rockwool as you plan is that you can push it into irregular shaped areas. So the choice of material does actually make a big difference, and buying premium at 1oomm thickness is not at the point of diminished returns. I used sheeps wool in some of the loft space but it is very expensive at 30 / 2.6m2 / 100mm If you live in the green or blue areas, we can sign you up to your local priority services registerifyou're over 60 or you rely on electricity for medical or mobility reasonsoryou have a hearing or visual impairment or a long-term health condition. According to the Energy Saving Trust, if you live in England or Wales, the floor should achieve a U-value of 0.25 W/mK. This site uses different types of cookies. Is there any way to isolate kitchen by lifting central part of the floors and keeping cabinets in place? home was raised some time before we bought it. I have read so much and very confused as to the best way to insulate the floor space. Andy. The reality is that if you have a suspended timber floor then the u-value before insulation is going to be upwards of 1.5 so achieving 0.34 W/mK is actually quite a result. Hope this helps and all the best with your project. If youd rather fully insulate your home, the cost can be high, so its best to coincide this with any renovation work you have planned. An alternative if you are not concerned with moisture issues would be rockwool (melts at around 1,000 C) but I would personally be happy using hemp insulation. Would certainly like it to be warmer though. Mineral wool insulation works well to reduce noise transfer between living areas, bedrooms and bathrooms.. Depending on available space, solid board insulation can then be screwed into the bottom of the joists to provide extra padding and draught proofing. Types of home insulation explained, Loft insulation, the complete guide to types & costs, Customer Warranty for Installation Services. If the existing floor covering is attractive then you may not wish to risk damaging it. This is because it requires digging up the old screed bed or concrete, fitting a thick layer of insulation, then replacing a thinner layer of screed back on top. Timber floors can be insulated by lifting the floorboards and laying mineral wool insulation supported by netting between the joists. Seal any gaps on the sides with expandable foam. as crawl space is very limited i have lifted most of the floor up and have fitted battens. Show you are a real person *
My question is more about noise reduction. Cheap and easy to fix too and will fit where your old air brick is. Your article is really interesting but unfortunately Im still unsure how best to go about insulating the floor! In this case would you recommend celotex type or earth wool ? It may not need a fan during the summer, Ive no idea whats best. Unclassified cookies are cookies that we are in the process of classifying, together with the providers of individual cookies. It is only a couple of days since it was installed. Also I had the opportunity when doing the lounge to explore the crawl space under the rest of the house and realised it was possible to do from underneath. This information is available as a freely downloadable PDF from this page. I would be quite surprised if it was one continuous timber between the two properties; there would be extra unnecessary cost and handling issues with having longer timber for no benefit. As there will be less cold air infiltration into the house itself, there is the potential for less ventilation in some areas of the home. Below the PIR Board is about 14in deep of space.
Plasterboard should then be fixed to the ceiling of the basement to provide fire resistance. Thanks a lot. Running this though the celotex U-value calculator (mineral wool modelled as 60mm celotex R = 2.7) in accordance with BS 13370:2007. Sorry if this is a silly question but would the semis share the same floor joists or would the party wall cut through the joists? Everywhere else I read tells me to fit a VCL on top, but your diagram for fitting from underneath does not show one. We are currently installing UFH in an early 1970s house, it has suspended floors. England and Wales company registration number 2008885. Read More, Stay up to date with the most recent Evergreen news, our latest projects and upcoming events. We are going to install mineral wall or similar between the joists supported by netting as you suggest but Im a little worried about how the vapour control layer attaches (or doesnt) to the wall. It continues to amaze me that people often overlook both the quality and suitability of their insulation. The first room I tackled was the lounge and decided to take up the floorboards to install it. If you have air bricks or ventilation bricks on the outside wall(s) of your house that are below floor level, you probably have a suspended timber floor. Suspended floors in older houses often have some damage in places; a result of raising floor boards when new central heating pipes were run or the house was rewired. They had to drill additional vents but then said all was ok to go ahead. There are also various acoustic insulation products that can be applied to the walls they would normally be covered with plasterboard or another material after installation. Behind the wood panelling is an air gap. If the joists are okay, you can fit insulation in between them and hold it in place with netting if necessary. As a DIYer with zero labour cost this is a significant expenditure compared to the materials cost for insulating the floor in a typical UK pre-war downstairs room. Your email address will not be published. Please can you advise me on insulation below the floorboards of a bedroom that half sits above a long porch or loggia that is unglazed. Before considering whether to add insulation, it is important that there is adequate cross-ventilation in the sub floor to remove any potential for damp and to keep the area dry. Hi Chris, thanks for your query. Multi-foil underlays reflect heat back into the house without raising the floor height by much. Insulating your floor underneath the concrete slab can help regulate the temperature and prevent over-heating in rooms that are south-facing or occupied for long periods of the day due to the thermal mass of the concrete. In practice that means there are about 5 or 6 bricks below the bottom of the joists (38-45cm or 15-18 of space). The gap below the raised floor is about 35cm. I have read about other houses but many have a larger space and have used spray foam. a) If you are insulating from above as you describe then you use a membrane to block moisture (what they call a vapour control layer which is impermeable to water) and put it above the insulation and below the new floorboards.
This is particularly important where joists are in contact with walls. The basements ceiling should then have plasterboard fixed directly to the undersides of the joists, to provide fire resistance and you can then fit more rigid insulation underneath the ceiling to benefit from even more insulation. Hi James, If your floor is above an unheated cellar or basement you will need to fit the insulation snugly between the joists and secure in place with netting if required. Where insulation is placed above the slab, the rooms will warm up more quickly when the heating is switched on. The original vents were just below the floorboards so we have had to use periscope style vent to let the air under the insulation board due to the ground level outside. If you are taking the floorboards up and the joists are irregularly placed and not straight then going for 100% flexible insulation supported by a breathable membrane may be easier. First off thanks for making the site and the guide as its a job that i am looking to do in the near future. Can you suggest any alternative to removing the panelling to insulate all the way to the exterior wall? While rock mineral wool is made from volcanic rock, basalt, dolomite and recycled slag from the steel industry. Your email address will not be published. I have seen examples where netting is used from underneath but this is not considered so effective at eliminating draughts. Many older houses with suspended timber floors in the UK have big draughts and inadequate floor insulation; this can cause cold feet as well as higher energy bills. The space will be sealed very tight once the heating system is installed also the floor will then be warm, I assume and this may cause more moisture. I need to insualte my cellar roof, but the cutting is going to be long and difficult as the joists are different sizes and angles between each one. The suspended floor above is draughty where we have restored the floorboards. Generally I have just used short battens at 90 degrees to the joist as support for the rigid board and then filled large gaps with expanding foam and taped the joist/board link with aluminium tape but I can see the attraction of running draught excluder it the full length. Installing under floor insulation can address both these problems. Hi Andres, We insulated under our 1800 year old granite farmhouse boarded floor with garden netting and mineral wool when new flooring was put down. It is suspended timber floor with airbricks fitted.
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When insulating from above this is the only practical way of doing it. Its also a good opportunity to insulate any underfloor piping you have access to. How much insulation you need will depend on the current U-value of your floor set up.
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