The second issue with rigid boards is that getting a leak-free fitting between joists is impossible unless you use expanding PU foam to fill any of the inevitable gaps (Ive done this job, and Im handy, and its just not realistic to cut a 100mm-thick foam board accurately and dead square to +/- 1mm and the old joists will NOT be perfect either!). For those undertaking it on their own homes it is more a judgement on which material is easier to work with and will take least time rather than simply material cost. England and Wales company registration number 2008885. The choice of membrane needs to allow air around joists to escape to the cold side. There are two impacts of thinner 4 (100mm) joists rather than 6 or 8. House is very cold and requires a breathable solution for the floor. The panneling seems quite well sealed but I am concerned that it will act as a giant heat-sink and there may be some draft as the cold air bypasses the floor insulation. Hemp is also used in solid floor insulation in the form of hempcrete (a hemp and lime mix) which is a breathable replacement for conventional concrete. Kind regards How about using Spray Foam Underfloor Insulation? One must check this Moisturebarrier.co.nz it gives us more info on this topic. As I understand it you need a building control notice for a thermal upgrade on an old property renovation. You can also subscribe without commenting. is this. Im guessing that your party wall is solid brick and that the joists in each property are supported by the party wall. PS if you are cutting PU or PIR boards, take GREAT care not to get the dust in your eyes it is extremely irritant and can really spoil your day. three
Maybe another commenter with more expertise in this area would be able to offer further insight. Thank you for the very informative article. They are needed to help ventilate the space under your floor and stop your floorboards rotting. Ive just found this site and its extremely helpful but I could use some advice. Jon. Having a timber floor insulated professionally, including filling the gaps between the floorboards and around the skirting, depends on the size and shape of the room and the insulation material used, but typically costs around 500. 
To achieve this standard, you will normally need at least 70mm of high-performance foam insulation, or 150mm of mineral wool, but this will vary depending on floor type, shape and size. For solid concrete floors, make sure that if they need to be replaced, your builder puts in insulation you have to insulate a floor when it is replaced in order to comply with building regulations. function() {
Timber floors can be insulated by lifting the floorboards and laying mineral wool insulation supported by netting between the joists. 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. The U-value is a measure of how quickly heat will travel through the floor. With this level of saving the payback time on a timber floor is around 7 years, while carrying out the work on a DIY basis will significantly reduce the costs and the insulation could pay for itself in around 2 years. Im edging towards using netting to support and then rock-wool insulation between the joists. With all things related to building it does depend on site conditions so if your house is in an area highly protected from winds then I would err towards the 1.5m level. Darren sanchez.
About us | CSE home page | Facebook | Twitter | FAQs | Factsheets | Contact, Sitemap | Accessibility | Using this website| How we use the information we collect, 2013 Centre for Sustainable Energy, St James Court, St James Parade, Bristol BS1 3LH | Registered Charity 298740 | Site by 375, Underfloor insulation being laid between the floor joists of a Victorian home, Getting the best from your gas or electricity supplier, Understanding your gas or electricity bill, Energy efficient glazing & high performance external doors, Mechanical ventilation with heat recovery, Making the most of your air source heat pump, If you live in the green or blue areas, we can sign you up to your local, you have a hearing or visual impairment or, This information is available as a freely downloadable PDF from this page. I had built an access panel in the lounge which allowed me to access the crawl space very easily. Thanks in advance. I did this to my 1911 terraced house and have plenty of air flow. This comes in various thickness (50mm and 100mm are the most common) and in a variety of sizes (2.4 x 1.2m being the most common). According to CIBSE Guide A (the bible as far as these sorts of things are concerned) in a 25mm unventilated cavity it can increase thermal resistance from 0.19 to 0.50 m2K/W which is a significant improvement. What are the pros and cons of using foam backed radiator reflector pinned to the battens to reduce the bridging effect of the joists?
Do u cover Peterborough at all pe2 8td 1930 bungalow with crawl space of 4ft under floor.roof has been done walls also completed. Thanks, Hi Naz, You must accept preferences cookies to view location-specific content. The benefit of using rockwool as you plan is that you can push it into irregular shaped areas. Thanks Jon, thats most helpful. tiles floor porcelain 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. You have to work round any existing heating pipes running under the floor as well as getting into cramped spaces. This is a good thing to do but it does mean that the cavity below the suspended floor is now colder and consequently there is more risk of condensation without adequate air flow via the air-bricks. If the concrete is above the insulation it can sometimes store heat during the day, which helps keep the room warm at night. as crawl space is very limited i have lifted most of the floor up and have fitted battens. So any moist air is removed by airflow from underneath the joists. Id be insulating from above. Guide to Best Practice on Retrofit Floor Insulation for Suspended Timber Floors, https://historicengland.org.uk/images-books/publications/eehb-insulation-suspended-timber-floors/heag086-suspended-timber-floors/, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/898872/suspended-timber-floors-underfloor-insulation-best-practice.pdf, https://great-home.co.uk/condensation-in-roofs/, https://www.wickes.co.uk/Rockwool-Sound-Insulation-Slab50mm/p/148841, 450 Million Boiler Upgrade Scheme Announced By Government, Green Home Grant Voucher Scheme Closes 31 March 2021, Hydrogen Heating Gets Boost In Government Green Industrial Revolution, Building Regulations: Current U-values for Insulation in Homes, Green Home Grant Voucher Scheme Live 30 September 2020, heat loss fromthe fabric of the building (walls, ceilings, floors. In fact, where this is the case, upgrading your floor insulation is required in order to comply with Building Regulations.
See Using Robotics for Underfloor Insulation of Suspended Timber Floors.The Department for Business, Energy & Industrial Strategy (BEIS) has also produced a Guide to Best Practice on Retrofit Floor Insulation for Suspended Timber Floors. timeout My experience of heat calculations on low emissivity materials is when an air cavity is involved so not sure how to approach it when there is no air gap. A plan for cables and pipes is also needed. Noise between solid party walls like this is nothing new; hearing the neighbours conversations through the party wall is a feature of this type of property! As a point of reference, building regulations for new homes set a maximum U-value (a measure of thermal resistance) of 0.13W/m2K for the floor. Please reload CAPTCHA. to the joists. The cold air from beneath the suspended timber floor then comes through the damaged floorboards, making the house and your feet feel cold. This will vary depending on insulation material and brand chosen, as well as floor type, shape and size. Mineral wool insulation comes in roll or batts (slab form).
Actis insulation make great products as an alternative to traditional pir and wool products and a lot easier to use. Alternatively, a recent innovation involves a robot applying spray foam insulation to the underside of the floorboards, which would avoid the need to take them up altogether. If the floorboards are tongue and groove then they will have to be removed in order and if they are well nailed down this can be a specialist task. Insulating and improving the airtightness of your floor can be a good first step on the road to a cosier home, saysChayley Collis at Green Building Store (opens in new tab). 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. The suspended floor above is draughty where we have restored the floorboards. Jon. I We'll assume you're ok with this, but you can opt-out if you wish. Some floorboards can warp over the years creating gaps. Installing underfloor insulation can address both these problems and give a payback on your investment in 5 years or less depending on whether you do it as a DIY job or use a professional. Also you need a way of pushing the rockwool into the space and then keeping it there with gravity working against you. Hope this helps and all the best with your project. Hi Andres, Notify me of followup comments via e-mail. Do I need low temperature heat pump radiators? To follow on from Miles comments the bridging in the joist will limit the effectiveness of the insulation, but the choice of material does make a large difference in overall U-value of the floor. Where the crawl space is limited on non existence then you may be forced to remove the floorboards or compromise and go for a less ideal option.Update August 2020: It is also worth checking out a robotic option which has been developed recently. They have the added advantage that they can be raised slightly higher above the ground so they dont get so blocked with earth, foliage or other debris. House is very cold and requires a breathable solution for the floor. If you do it from under the floor use mineral wool. Insulating a suspended timber floor can eliminate floor draughts and reduce heat loss through the fabric of the floor at the same time. This ensures your home is protected as much as possible. Sophie Vening is a freelance journalist and editor with more than 16 years experience writing about homes and properties. Read More, Stay up to date with the most recent Evergreen news, our latest projects and upcoming events. If you are adding extra insulation to your floors, the work will need to comply with the relevant building regulations for where you live. Your article is really interesting but unfortunately Im still unsure how best to go about insulating the floor! I think the main debate would be over whether this is more or less airtight than a rigid board material which is gap filled with expanding foam and then taped. I think any method that stops air flow (ventilation heat losses) is going to help, whether its tape or draught excluder. Weve got more information about energy saving home improvements here. I totally agree with your comments on the heat loss through the joists, which is going to pull the u-value down whatever insulation material you use. Its always advised to shop around for quotes before having any work carried out. If there are gaps, then the air blows through and your expensive board might as well not be there. My question is more about noise reduction. As you say, the simplest way is to batten out the joists and fit rigid insulating board. Hi Miles 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. Would there be benefit stapling thermal foil to the bottom of the joists? It the floorboards have been removed then the insulation material is held in place with netting underneath (or a vapour permeable membrane) and then a vapour control layer (VCL) is applied above the joists. Your 14 depth of the space beneath the floor sounds pretty typical and for this depth the advice is that vents should be spaced every 1.5-2m around the outside wall. Theres a chance that some unforeseen expenses will arise. Having more rather than fewer vents will move the moist air faster so should reduce damp. Check out these female-friendly bedroom ideas that are the perfect mix of chic and sophistication, The new range is a dupe for the stylish Novogratz lockers available at Next. Celotex / Kingspan typePIR thermal insulation board. Quality mineral wool will stop draughts as you can push it near walls and will work really well in the cold days and it is much cheaper. However this has not affected its use in underfloor insulation in domestic homes. Depending on available space, solid board insulation can then be screwed into the bottom of the joists to provide extra padding and draught proofing. This may be a really stupid question but is adding a layer of insulation OVER the existing suspended floorboards and under a new layer of plywood underlay topped with new floorboards possible?? I havent seen any data one way or another but generally when using rockwool the recommendation seems to be to add a vapour control or vapour breathable membrane (depending on which way you are working) and this is partly to reduce air infiltration. This is extra activity and cost. Apologies for the long and rambling question (its a long and rambling cellar!). Everyones heard about thermal bridging, but the point here is that it can easily make a mockery of buying expensive high performance insulation for the bits between the bridges. Thanks for your comments. From a thermal comfort perspective, it does appear that feet are particularly sensitive to colder temperatures, so addressing floor draughts can help improve comfort levels. Im assuming silver side down would be best. var notice = document.getElementById("cptch_time_limit_notice_55"); I would suggest to speak to your local council before you do this. There is still about 20cm of space (after fitting PIR board) for the air to circulate u see the floor. Are there any options here, short of making a mess with the power off. Is there a risk of condensation and damp? This will raise the level of the floor, so you will need to make sure doors are trimmed shorter to make room for the insulation. We are looking at installing underfloor insulation under suspended timber floor of a bungalow and are engaging with a contractor as part of green homes grant. If the insulation is above the concrete the room will heat up more quickly in the morning. Properties built pre-1920 often didnt have air bricks for ventilation or a DPC (Damp Proof Course) so damp may be a problem that needs sorting before you think about floor insulation. Solid floors are insulated using rigid insulation foam, which can be fitted either above or below the concrete. Make sure your chosen thermal underlay has a high tog rating or R-value (these are both measurements of thermal resistance). As you can imagine, theres a lot of cold air down there! A brilliant piece of content with some common questions answered! Unlike the floor joists it is not a structural element (not load bearing) and it would not be considered a potential source of ignition. (Image credit: Future PLC/Future plc/David Brittain), (Image credit: Future PLC/Dominic Blackmore), The home of great ideas for more than 100 years, A couple transformed this dated caravan into a light-filled, stylish space saving 1000s, Bedroom ideas for women - 12 sassy schemes that are feminine and fun, Aldi's new kids bedroom furniture is so chic we want it for our own bedrooms. Or should it be a solid DPM type membrane? Nice article, installing underfloor insulation may not be very cost effective or save you money in the long run, but it is certainly very comfortable for people living in the house. Kind regards With less ventilation there may be a risk of damp near the main sources of moisture (usually from cooking or showing) so it is important to have adequate extraction in these areas.
To achieve this standard, you will normally need at least 70mm of high-performance foam insulation, or 150mm of mineral wool, but this will vary depending on floor type, shape and size. For solid concrete floors, make sure that if they need to be replaced, your builder puts in insulation you have to insulate a floor when it is replaced in order to comply with building regulations. function() {
Timber floors can be insulated by lifting the floorboards and laying mineral wool insulation supported by netting between the joists. 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. The U-value is a measure of how quickly heat will travel through the floor. With this level of saving the payback time on a timber floor is around 7 years, while carrying out the work on a DIY basis will significantly reduce the costs and the insulation could pay for itself in around 2 years. Im edging towards using netting to support and then rock-wool insulation between the joists. With all things related to building it does depend on site conditions so if your house is in an area highly protected from winds then I would err towards the 1.5m level. Darren sanchez.
About us | CSE home page | Facebook | Twitter | FAQs | Factsheets | Contact, Sitemap | Accessibility | Using this website| How we use the information we collect, 2013 Centre for Sustainable Energy, St James Court, St James Parade, Bristol BS1 3LH | Registered Charity 298740 | Site by 375, Underfloor insulation being laid between the floor joists of a Victorian home, Getting the best from your gas or electricity supplier, Understanding your gas or electricity bill, Energy efficient glazing & high performance external doors, Mechanical ventilation with heat recovery, Making the most of your air source heat pump, If you live in the green or blue areas, we can sign you up to your local, you have a hearing or visual impairment or, This information is available as a freely downloadable PDF from this page. I had built an access panel in the lounge which allowed me to access the crawl space very easily. Thanks in advance. I did this to my 1911 terraced house and have plenty of air flow. This comes in various thickness (50mm and 100mm are the most common) and in a variety of sizes (2.4 x 1.2m being the most common). According to CIBSE Guide A (the bible as far as these sorts of things are concerned) in a 25mm unventilated cavity it can increase thermal resistance from 0.19 to 0.50 m2K/W which is a significant improvement. What are the pros and cons of using foam backed radiator reflector pinned to the battens to reduce the bridging effect of the joists? Do u cover Peterborough at all pe2 8td 1930 bungalow with crawl space of 4ft under floor.roof has been done walls also completed. Thanks, Hi Naz, You must accept preferences cookies to view location-specific content. The benefit of using rockwool as you plan is that you can push it into irregular shaped areas. Thanks Jon, thats most helpful. tiles floor porcelain 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. You have to work round any existing heating pipes running under the floor as well as getting into cramped spaces. This is a good thing to do but it does mean that the cavity below the suspended floor is now colder and consequently there is more risk of condensation without adequate air flow via the air-bricks. If the concrete is above the insulation it can sometimes store heat during the day, which helps keep the room warm at night. as crawl space is very limited i have lifted most of the floor up and have fitted battens. So any moist air is removed by airflow from underneath the joists. Id be insulating from above. Guide to Best Practice on Retrofit Floor Insulation for Suspended Timber Floors, https://historicengland.org.uk/images-books/publications/eehb-insulation-suspended-timber-floors/heag086-suspended-timber-floors/, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/898872/suspended-timber-floors-underfloor-insulation-best-practice.pdf, https://great-home.co.uk/condensation-in-roofs/, https://www.wickes.co.uk/Rockwool-Sound-Insulation-Slab50mm/p/148841, 450 Million Boiler Upgrade Scheme Announced By Government, Green Home Grant Voucher Scheme Closes 31 March 2021, Hydrogen Heating Gets Boost In Government Green Industrial Revolution, Building Regulations: Current U-values for Insulation in Homes, Green Home Grant Voucher Scheme Live 30 September 2020, heat loss fromthe fabric of the building (walls, ceilings, floors. In fact, where this is the case, upgrading your floor insulation is required in order to comply with Building Regulations.
See Using Robotics for Underfloor Insulation of Suspended Timber Floors.The Department for Business, Energy & Industrial Strategy (BEIS) has also produced a Guide to Best Practice on Retrofit Floor Insulation for Suspended Timber Floors. timeout My experience of heat calculations on low emissivity materials is when an air cavity is involved so not sure how to approach it when there is no air gap. A plan for cables and pipes is also needed. Noise between solid party walls like this is nothing new; hearing the neighbours conversations through the party wall is a feature of this type of property! As a point of reference, building regulations for new homes set a maximum U-value (a measure of thermal resistance) of 0.13W/m2K for the floor. Please reload CAPTCHA. to the joists. The cold air from beneath the suspended timber floor then comes through the damaged floorboards, making the house and your feet feel cold. This will vary depending on insulation material and brand chosen, as well as floor type, shape and size. Mineral wool insulation comes in roll or batts (slab form).
Actis insulation make great products as an alternative to traditional pir and wool products and a lot easier to use. Alternatively, a recent innovation involves a robot applying spray foam insulation to the underside of the floorboards, which would avoid the need to take them up altogether. If the floorboards are tongue and groove then they will have to be removed in order and if they are well nailed down this can be a specialist task. Insulating and improving the airtightness of your floor can be a good first step on the road to a cosier home, saysChayley Collis at Green Building Store (opens in new tab). 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. The suspended floor above is draughty where we have restored the floorboards. Jon. I We'll assume you're ok with this, but you can opt-out if you wish. Some floorboards can warp over the years creating gaps. Installing underfloor insulation can address both these problems and give a payback on your investment in 5 years or less depending on whether you do it as a DIY job or use a professional. Also you need a way of pushing the rockwool into the space and then keeping it there with gravity working against you. Hope this helps and all the best with your project. Hi Andres, Notify me of followup comments via e-mail. Do I need low temperature heat pump radiators? To follow on from Miles comments the bridging in the joist will limit the effectiveness of the insulation, but the choice of material does make a large difference in overall U-value of the floor. Where the crawl space is limited on non existence then you may be forced to remove the floorboards or compromise and go for a less ideal option.Update August 2020: It is also worth checking out a robotic option which has been developed recently. They have the added advantage that they can be raised slightly higher above the ground so they dont get so blocked with earth, foliage or other debris. House is very cold and requires a breathable solution for the floor. If you do it from under the floor use mineral wool. Insulating a suspended timber floor can eliminate floor draughts and reduce heat loss through the fabric of the floor at the same time. This ensures your home is protected as much as possible. Sophie Vening is a freelance journalist and editor with more than 16 years experience writing about homes and properties. Read More, Stay up to date with the most recent Evergreen news, our latest projects and upcoming events. If you are adding extra insulation to your floors, the work will need to comply with the relevant building regulations for where you live. Your article is really interesting but unfortunately Im still unsure how best to go about insulating the floor! I think the main debate would be over whether this is more or less airtight than a rigid board material which is gap filled with expanding foam and then taped. I think any method that stops air flow (ventilation heat losses) is going to help, whether its tape or draught excluder. Weve got more information about energy saving home improvements here. I totally agree with your comments on the heat loss through the joists, which is going to pull the u-value down whatever insulation material you use. Its always advised to shop around for quotes before having any work carried out. If there are gaps, then the air blows through and your expensive board might as well not be there. My question is more about noise reduction. As you say, the simplest way is to batten out the joists and fit rigid insulating board. Hi Miles 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. Would there be benefit stapling thermal foil to the bottom of the joists? It the floorboards have been removed then the insulation material is held in place with netting underneath (or a vapour permeable membrane) and then a vapour control layer (VCL) is applied above the joists. Your 14 depth of the space beneath the floor sounds pretty typical and for this depth the advice is that vents should be spaced every 1.5-2m around the outside wall. Theres a chance that some unforeseen expenses will arise. Having more rather than fewer vents will move the moist air faster so should reduce damp. Check out these female-friendly bedroom ideas that are the perfect mix of chic and sophistication, The new range is a dupe for the stylish Novogratz lockers available at Next. Celotex / Kingspan typePIR thermal insulation board. Quality mineral wool will stop draughts as you can push it near walls and will work really well in the cold days and it is much cheaper. However this has not affected its use in underfloor insulation in domestic homes. Depending on available space, solid board insulation can then be screwed into the bottom of the joists to provide extra padding and draught proofing. This may be a really stupid question but is adding a layer of insulation OVER the existing suspended floorboards and under a new layer of plywood underlay topped with new floorboards possible?? I havent seen any data one way or another but generally when using rockwool the recommendation seems to be to add a vapour control or vapour breathable membrane (depending on which way you are working) and this is partly to reduce air infiltration. This is extra activity and cost. Apologies for the long and rambling question (its a long and rambling cellar!). Everyones heard about thermal bridging, but the point here is that it can easily make a mockery of buying expensive high performance insulation for the bits between the bridges. Thanks for your comments. From a thermal comfort perspective, it does appear that feet are particularly sensitive to colder temperatures, so addressing floor draughts can help improve comfort levels. Im assuming silver side down would be best. var notice = document.getElementById("cptch_time_limit_notice_55"); I would suggest to speak to your local council before you do this. There is still about 20cm of space (after fitting PIR board) for the air to circulate u see the floor. Are there any options here, short of making a mess with the power off. Is there a risk of condensation and damp? This will raise the level of the floor, so you will need to make sure doors are trimmed shorter to make room for the insulation. We are looking at installing underfloor insulation under suspended timber floor of a bungalow and are engaging with a contractor as part of green homes grant. If the insulation is above the concrete the room will heat up more quickly in the morning. Properties built pre-1920 often didnt have air bricks for ventilation or a DPC (Damp Proof Course) so damp may be a problem that needs sorting before you think about floor insulation. Solid floors are insulated using rigid insulation foam, which can be fitted either above or below the concrete. Make sure your chosen thermal underlay has a high tog rating or R-value (these are both measurements of thermal resistance). As you can imagine, theres a lot of cold air down there! A brilliant piece of content with some common questions answered! Unlike the floor joists it is not a structural element (not load bearing) and it would not be considered a potential source of ignition. (Image credit: Future PLC/Future plc/David Brittain), (Image credit: Future PLC/Dominic Blackmore), The home of great ideas for more than 100 years, A couple transformed this dated caravan into a light-filled, stylish space saving 1000s, Bedroom ideas for women - 12 sassy schemes that are feminine and fun, Aldi's new kids bedroom furniture is so chic we want it for our own bedrooms. Or should it be a solid DPM type membrane? Nice article, installing underfloor insulation may not be very cost effective or save you money in the long run, but it is certainly very comfortable for people living in the house. Kind regards With less ventilation there may be a risk of damp near the main sources of moisture (usually from cooking or showing) so it is important to have adequate extraction in these areas.