I'm not saying this is the best thing to use. Hi, I'm doing a kitchen modernisation in my ex-Council house which was built in 1947. Fibreglass 1. 22 August 2019 at 10:27AM. Start of next year i will be putting in my finished floor in our new extension, as it stand we got it water tight late last night with the glazing. Yup so the plan is: Existing garage is concrete which is a 75mm lower than the current house level. This should be laid on a bedding material such as screed which doesn’t damage the sheet and has fully sealed joints. In this article, I am going to give you the low-down on liquid DPM, where and how it is used and some of the things you need to consider. will come down and meet the insulation under the screed so the screed is totally floating. 67. Deleted member 25896, Feb 2, 2021 #5. not bonded to the base – typically where a DPM is placed under the screed. DPM Membranes for Concrete Floors A range of high quality DPM membranes from Capital Valley Plastics, designed for use with solid concrete slabs. 3. In terms of where the insulation should be placed, it can either be placed under the slab or between the. Buy Now. Find. 1955 house, recently moved in and presuming no DPM under concrete slab. sandwiched under the screed, were also common and usually in liquid form, e. Spoke to makers of UFH system. Looking for best method to both level and damp proof the concrete, to then be covered with a thin layer of celotex, then engineered wood. Insulation sheets should be laid tightly together with the joints staggered to avoid movement. This site contains a wealth of information on our extensive product range, along with a selection of videos demonstrating their application. This should be laid on a bedding material such as screed which doesn’t damage the sheet and has fully sealed joints. Figure 3: Concrete masonry foundation wall and concrete floor. There are many proprietary screeds on the market and information about these can be obtained from the manufacturer. Kitchen floor, underfloor heating, screed and DPM. The difficulty is getting the underneath concrete to have a flat surface at exactly the right level. 5m) It will have 50mm insulation boards on top of it, followed by 18mm/22mm. F. SikaBond® Rapid DPM is a single part moisture curing polyurethane. View complete answer on allthingsflooring. Used the primer neat as guidelines suggested. Hi, I have an area of approx 6m by 3m on a ground floor extension which is block and beam construction, that I now need to insulate and screed to finished floor height. The 40mm between the joists is about 0. Use polyethylene sheeting to create a waterproof membrane to ensure that there is no leakage of the screed when it is pumped in wet. DPM’s can be applied to either a suitable blinding layer under the slab or internally to the top of the slab. Flexible - easy to detail and install on site. 40mm traditional sand and cement screed. If in the screed then no problem with this. Don't use a bitumen at all, you are correct eventually your screed will fail. Use screed on top of a concrete base to give your floor a level and smooth finish. Liquid DPMs gave the best protection but were more expensive. 0m is a low density polythene membrane for use under floor screeds which are not subject to hydrostatic pressure, to protect buildings against moisture from the ground. not really, you said that you intended to use DPM under SLC, compound won't adhere to dpm and if will will install tiles to the SLC and it will crack your tiling will be spoiled, you can do SLC, next apply liquid DPM and install tiles to it- that's the way in my opinion. The DPM should extend up the external foundation walls to meet. blocking/nogging for support of plasterboard 43mm x 38mm. A damp proof membrane (DPM) is used to create a barrier between a concrete (or screed) subfloor and the floor covering that is laid on top such as wood, ceramic or quartz tiles, laminate or carpet. framing joints secured with not less than 2 nails per joint. com. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. One thought is to plug it at the junction under the draincover and then screed round it, and lay floor over; then it can be reinstated in future if ever needed. I am happy to employ gs guy to do pipe and install boiler but don't want to be calling the guy several times months appart, hence the. Side extension refurb: old concrete slab is uneven with a line of about 10mm difference in heights down middle, and dpm under screed is visibly not 100%, with a few gaps. Greater thickness of screed may lead to a colder floor. This DPM is a ‘thick’ plastic sheet mostly 1000 – 1200 gauge polythene material. Hi All, I'm purchasing a new build and want to put Amtico Spacia down throughout the downstairs. A flat duct could now be layed over concrete (150×50 mm) this would encroach into insulation but as building regs are 75mm on floor insulation only 25mm. Seems fine so far. Developer has quoted £3744 for approx. All modern buildings have what is known as a Damp Proof Course. The guidelines state that a damp proof membrane that is placed under the flooring should be around 1200 gauge and constructed of polyethene. 150mm PIR insulation. I intend to consult BC but would like to educate myself before I speak with them Thanks in advance. LKAB Minerals +44 (0) 7966 651006. DPC and DPM are lapped together at this stage. T ·Öà 4 ·Öò 8 ·Ñ• 2, Jun 15, 2007. Hence we always say DONT apply a surface dpm to a subfloor subject to rising damp. He intended to stick the floor to the bitumen DPM. Will prim t be okay as primer on top of turbo? Thanks Pete Unless designed otherwise, the minimum specification for all partitions should be: sill and head plates 63mm x 38mm. For this, a metal mesh standing with plastic pillars ( (feet) will be laid before the concrete is. Don't think it will make much difference tbh, if you go the timber route use 22mm plywood instead of chipboard though. As a waterproofer, BAL DPM is an easy two-coat system when used with BAL Self-Adhesives Butyl Tape in corners and junctions. 12) Tiles glued. It has had an extension about 50 years ago and that is the problem room as the flooring was laid without any DPM under the existing concrete floor, so there are some rising damp issues (I think). I 've dug down and put 100mm of concrete down will liquid dpm to meet up with the existing dpm and 50mm screed ontop easy. Location. A section of the old screed layer has broken up around the edge of the patio door threshold. 300 dries very hard Bitumen is soft so not compatible. The old adhesive should of been removed. In the attached photo I have removed poorly laid DPM and insulation boards with a view to starting again. Cement screed is the most commonly installed type of screed and is suitable for both interior and exterior surfaces. Damp proof membranes (DPM) A DPM should be a minimum thickness of 1200g polythene and linked to the DPC with a minimum 100mm overlap. LAY DAMP PROOF MEMBRANE. Damp Proof Membrane is intended for use within solid concrete floors to prevent the rise of moisture or damp through structure flooring. If its not right. Note though that this will raise the floor level by 75-100mm (depending on the insulation). 25W/m 2 K to meet with building regulations, even if you didn’t plan to. As with the Kooltherm installation, start by ensuring a clean and level surface. link with wall DPCs to form an impervious barrier to prevent moisture reaching the interior of the dwelling. #2. com. It should accommodate 0mm to 5mm (or thereabouts) It will cover an area of 26m2 (4m x 6. Silicone mastic is the way to go. do I still need a DPM under that insulation? it is internal and sitting on a structural slab that is wrapped in DPM externally. Kingspan GreenGuard is available in a range of compressive strengths starting at 300 kPa 10% compression. Moisture in the base will impede the drying of the screed. Can be used as a Damp Proof. I would think a strip out and start again would be your best option, you should consider where/why there is water evident before. A DPM should be impermeable to water in liquid or vapour form and should be tough enough to withstand possible damage during laying of screeds, concretes or floor finishes. It is essential that this. Brief background: After buying a 1960s semi in south Birmingham house last year, and spending the summer managing (a) complete rewire; (b) installation of satellite and Ethernet wiring to all rooms; (c) plastering to make good chasing from (a) and (b); (d. DPM sheets should be overlapped by at least 300mm. First, divide the floor up. The surface should be of sufficient quality and. Diagram B39 - Proper sealing. As a rough guide, laying conventional screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. Water is added to ensure a thorough mix and to aid workability. Guide Underfloor heating A guide for house builders NF71 NHBC Guide to Underfloor Heating 2nd draft RH. enquiries@visqueen. It is important to ensure that a proper seal is achieved around all services. The surface should be of sufficient quality and. 45sqm to supply and fit. We always remove the masonry below allowing the floor screed to have a bit of 'meat' to help overcome the differential movement. DPM is usually below the concrete, then the insulation, then a polythene sheet to stop the insulation floating as the screed is poured. Liquid DPMs gave the best protection but were more expensive. Any advance on laying 75mm kingspan directly on existing screed with DPM beneath, then laying 18mm T&G moisture resistant chipboard. Which way would you go, 1000 gauge plastic under slab OR liquid dpm between slab and screed? renovateduk, Jul 17, 2009 #3. -markie-, Feb 10, 2020. I would lay the DPM straight onto the existing and screed over. A standard sand/cement screed would need to be laid at a minimum depth of 65mm for a domestic property. Also, even with 80mm screed directly over Celotex the sab can feel a bit "hollow". O and the Answer to Mapei and Uzin is no. It is a thermally effective solution that is equally efficient in concrete floors, beam and block floors, and suspended timber floors. In terms of where the insulation should be placed, it can either be placed under the slab or between the slab and the floor screed. 0. You could asphalt but it will eventually fail one day and you'll need to do it again although it is the cheaper immediate option. also alot of the insulation manufacturers specify a 500/1000 gauge membrane between the insulation and the screed inkpad, Aug 6, 2009 #7. Assuming that the damp proof membrane (dpm) under the concrete has failed in areas then yes you possibly would get the odd patch of dampness showing in the floor. Ask the mods to move your thread to Flooring forum and see: dazlight Fri 29 aug 2020 for a specific response to a difficult surface. Diagram B38 - DPM lapping under DPC for thickness of inner leaf. Discussion in ' Builders' Talk ' started by barnjules, Jan 30, 2017 . Only one coat though. #1. If you're laying Karndean over existing flooring, be sure it is properly prepared. celotex goes UNDER concrete. 5m2 at 1mm thickness 1. When stripping the bathroom, the area under the bath tub was bare concrete, lower than the rest of the "black" floor throughout the property. Also checking, the dpm is meant to be underneath the insulation? Two options: - Jablite Jabfloor 70 100mm (or jabfloor 100 or 150 grade but not sure what the difference is, building merchant sells the 70) - Xthratherm/Kingspan 100mm. Bring the membrane up the surrounding foundation walls until it is just high enough to connect with or form the wall damp proof course. This means of course I can't get a DPM under the slab; is it ok to put the DPM over the concrete slab, and then put down 50mm insulation and then 100mm screed? Ed209 , May 1, 2020 #1Assuming that the damp proof membrane (dpm) under the concrete has failed in areas then yes you possibly would get the odd patch of dampness showing in the floor. Maybe better to use a fibre based leveling compound instead, like Granfix Fibreflex 50 or similar. It has excellent adhesion to. The job is under Building control, so I'm sure the inspector will like a nice solution as well! The shower can't be lifted higher (elderly. 10) Timber block between U channel and Cavity Weep Holes 11) Galzing unit (window/glass) 12) Tiles glued 13) Polypropylene 14) Screed 15) DPM under screed 16) Concrete slab 300mm 17) DPM under. Which is supposed to be a DPM equivalent. At its deepest it’s 150mm, what I’m stuck with is the builders trying to push on with the job. Lay and level the concrete slab, allowing sufficient time to dry out, as per BS 8203. The rest of the floor will be as follows (top down); flooring. Would a liquid dpm work,in past I had similar problem, I've just poured some liquid dpm in to the hole & help it with a trowel to find it's way under the concrete,seem to work as I never had damp issue when I moved indoor stop cock to new position at previous place & here when I laid new pipe under utilty floor after clay pipe failed, 10 years on, not. Checkatrade offers the following guide: Electric underfloor heating cost. Hoping the power of the Screwfix forum can help with a totally baffling problem we are having with our new extension. Walkable in 6 hours. Dig the oversite ground to whatever height allows your hardcore, insulation, blinding, slab,screed. Yes it is a small breach on regs but would be up to building control to decide. Damp proof membranes (DPM) A DPM should be a minimum thickness of 1200g polythene and linked to the DPC with a minimum 100mm overlap. Small domestic areas that are going to have carpet, wood or synthetic floors as the final surface are ideal to use in conjunction with. heated levelling screeds. The reasoning behind the 'sub-base:bedding' school of thought is that the membrane prevents the bedding from trickling down or being washed into any voids within the sub-base material, while the 'sub-grade:sub-base' orthodoxy, in which I include myself, maintains that keeping the sub-base material from mixing with the sub-grade, and reducing or. New-build install: £120 to £135 per square metre. The polyethene slip membrane installed over the insulation must be overlapped and sealed to prevent loss of screed. Then a primer like the one you have at 4-1 then if needed another coat at 2-1. Suitable for most construction damp proofing requirements. A poorly compacted, damaged or weak screed should be completely removed by mechanical means and reinstalled correctly. The main issue you need to remember about the DPC at the external walls is to have an upstand on the inner leaf and slope down to the other leaf. This barrier is intended to stop moisture passing from one to the other. To ensure a level finish to the floor, a layer of screed is added over the top of the concrete, which consists of sand and cement. Description. 17) DPM under slab. The idea is that you are to prevent any screed material from falling down any joints and coming into contact with the cold slab. Misinformed on this as he had put a dpm under the chipboard. Consideration should be given to applying the DPM to the top of the slab, as the installation and moisture sensitive internal finishes are then protected from any residual moisture in the concrete. As you are always relying on the subfloor surface strength you are always at risk if there is no sheet DPM under the floor as it will be under pressure. This generally takes 1-2 days, depending on the thickness of the floor screed. Pumped anhydrite floor screeds are not much dearer than ready-mix sand/cement, costing around £25/m3 (laid. Prime and reapply , then screed to level and tile. Apply ARDEX DPM 1 C to protect the floorcovering installation from residual construction moisture and ground bearing moisture. Firstly, there was no need to use a liquid dpm if you used underlay with a built in vapour barrier. 100m² per roll. with the concrete but the insulation. Fast drying screed cost. BONDED VERSUS UNBONDED SCREEDS Bonded topping screed installations are the most common as this allows the minimum thickness (15mm) to be applied thus limiting the weight load on the structure. Screed. The polythene damp proof membrane (DPM) – generally a 1200 gauge- can now be rolled out into place ensuring the perimeter abutments are adequately covered. The installation of a liquid damp proof membrane is a vital stage in the construction process, for both new builds and refurbishment work where a structural DPM may be missing or damaged, or where residual construction moisture is present in the floor. having a solid wall causes damp bridging problems for the floor (there is a dpm on top of the floor anyway, but the beam and block is supposed to sit on a dpc) as there is no cavity. But if you’re on a tight schedule, allow at least 7 days before applying your vinyl floor covering. I'm looking for opinions on the best self leveling screed to use on my slightly wonky concrete garage floor. Doggit. It may be applied onto either a solid in-situ concrete ground floor slab or onto a precast concrete floor unit. Below are a few photos of the extension so far which show the dpm that’s under the slab coming up next to the opening. As to joining - take bricks down to the bottom of the insulation later and run your insulation (which I presume is celotex type) into the opening, screed over insulation level. 4 Screed. 25 Apr 2010. the screeder I use sets up a laser level and sets out his screed to that, the finish is always really good, much better than using long levels to transfer from section to section. . There are two main options: 1. 2: Fill the gaps with concrete, lay a DPM over it, insulation, then a concrete / fibre screed. Be very careful by rushing. Laying new floor - needs DPM? dunroving Posts: 1,881 Forumite. When applied on top of screed, it needs to have a further coating to protect it from damage such as laminate, tiles, vinyl, wood and carpets. This barrier is intended to stop moisture passing from one to the other. We’d recommend using timber battens to act as a guide – apply a small amount of screed to the flooring to lay the battens on, and lay the battens in strips across the floor. jeds. By definition, Relative Humidity (RH) is a measure of the amount of water vapour present in the atmosphere relative to the amount of water vapour it can hold at that given temperature. rev 2023. As a rough guide, laying a conventional sand/cement screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. The installation of the DPM is extremely important as this acts as a barrier to prevent damp rising up through the substrate, from the ground below. Care must be taken to a) ensure there are no holes or tears in the sheet that could allow. Location. Hull. 5mt x 4mt rolls | £ 56. £14 per m2. Answered 18th Aug 2020. They can be used under resin screed finishes and are applied in thinner sections than standard cement screeds. UZIN has the right floor damp proof membranes for damp proofing floors. Epoxy DPM itself (the actual product epoxy) wont fail once set. •Suitable for use on cement/sand screeds containing water based under floor heating systems •Apply ARDITEX NA direct without priming JUNE 2019 (SUPERSEDES MARCH 2018) PRODUCT DATA SHEET (43) V. The insulation should not be stepped as this can act as an anchor point and cause cracking in bridging or on the screed under movement and cause weak spots in a void underneath. For a self-levelling screed a system such as Flowcrete UK’s Hydraseal would be used. Mark El-Kadhi New Member. You need a flooring professional to use an epoxy liquid DPM and screed suitable for this area and is not a job you should think to attempt 1 pinhole is a failed floor. #5. 4 Screed. You are therefore at the edge of the joists capability. Pro-Screed Gold can be applied from depths of 2mm to 12mm in one application and with aggregate it can be applied up to 30mm thick. The current recommendations for an effective damp proof membrane are that the ground should be constructed using screed with the damp proof membrane laid either on top or below that layer. Nice. weberfloor flex is a self-smoothing floor levelling compound — often incorrectly referred to as a self levelling screed or self levelling floor compound — which can be tiled onto and is an easy screed for applying onto floor substrates subject to some movement, such as wood or underfloor heating. The company keeps abreast of market developments by. 5. Roger Kenworthy on 2021-08-13 17:59:40: Question:Durability: A befittingly developed floor screed will outlast the else modules of the building. Fintan has been involved extensively in a deep energy retrofit of a property to the Enerphit standard in the west. Pre screeding, you lay the DPM, install the insulation sheets and create vertical upstands of insulation block around the outside perimeter of the wall. weberfloor DPM can be applied on to concrete or cement based screed surfaces with a. It is usual practice to lay vent pipe under concrete and dpm. Can be used over underfloor heating. Unfortunately soon after it was laid it started crumbling and holes were appearing in places, as electricians and plasters came in to do their work and walked all over it, they did put black sns plastic sheeting down to protect it though. For example, when installing Celotex under floor. The DPM (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. – the UK’s leading manufacturer of flooring adhesives and floor preparation products for the contract flooring industry. Stack Exchange Network. Notch7. Warm construction build-up would be: - Sand blinded sub-base. Then mix up the high performance stuff as that is fibred and can be taken to a feather edge. Where a concrete slab or a screed is to be poured on top, the VCL will also protect the foil face of the board from alkalis within the concrete, and stop poured concrete opening board joints and causing a thermal break. The buildup is. screed thickness. Screed above dpm. As a rule self levelling screeds need an active DPM at some point below them other wise they will likely de-bond due to damp and this could be the reason it seems to be lifting easily. For traditional screed, the usual total will fall within the range £18. In addition to the damp proof membrane (normally a 1200-gauge polythene sheet below the insulation), a 500-gauge polythene VCL. 17 May 2010. Before screeding can commence the area to be screeded must be made watertight to prevent leakage. FlexiDry said: Yes laying the screed direct onto insulation is standard practise for a floating floor. For unbonded and floating screeds, a DPM may be specified between the base slab and the screed. All other sheet membranes can be used with unbonded toppings. RFC Liquid Damp Proof Membrane (DPM) is a professional 2-component applied surface primer. My question is thoughts on floor layout. This will. Insulation would be a good idea, but it also may not be a bad idea to knock the whole thing down and start again if the walls are only 4", the floor is rough, and the roof probably leaks too. Applying Damp Proof Membranes. "Your insurance company should be able to instruct property drying. 20 mm thickness should do it and im looking for the. DPM's must be carefully protected where folded up the perimeter walls, and lapped under the DPC particularly at door openings. The DPM can be used as either below the slab application, directly below the flooring surface or in a sandwich construction, between base concrete and the screed. . I want to level my workshop floor. ) • Floating (used to enable installation of thermal or impact sound insulation). Ideal for use where there is no functioning structural DPM (common in older properties). The liquid membrane forms a strong seal and makes a permeable layer to enable moisture to evaporate off. sandwiched under the screed, were also common and usually in liquid form, e. Drybase Liquid-Applied DPM should be used in situations where the final surface is going to be covered. These black DPMs can also be used with underfloor heating - under normal operating conditions this will not adversely affect the membrane. The floor originally had a carpet laid on top of the tiles, when I lifted it nothing felt, looked or smelled damp. C. 6 March 2017 at 8:04PM edited 6 March 2017 at 8:59PM. This process is not 100% foolproof and so during screeding an extra pair of hands is useful to tuck the materials together until the weight of. For rafts, DPM and screed must be on top of raft and screed must be at least 65 mm thick. not a good idea man. 4m x 50m x 500g (200sqm) Black Polythene Vapour Control layer 4m x 25m (100sqm) TPS. Why is a. Manchester • Member since 5 Jun 2015 • 64 jobs, 95% positive feedback. The DPM is tied into the internal leaf of masonry. It’s only to stop the screed running under the insulation. If there was no dpm I would suggest a uniformal distribution across the whole floor. There needs to be one under the beams that rest on the internal wall. Proposed floor is pitch pine boards secret-nailed to 2 x 2 inch battens with insulation between, onto a concrete floor not known to have a DPM under it; therefore, DPM to go under the battens. screed (with UFH) 75mm. British Standard (8204:1) says minimum 65mm for domestic floating. The work falls under building regs part L and you need minimum 70mm PIR insulation. This can only normally be guaranteed if its an new build or extension and most houses have been sold, inherited etc. Let’s hope you have a good water table as that’s the wrong dpm used. carpet, tiles etc. 001 Ardex Australia 201550mm insulation would be better than nothing be it under screed or timber. If the wall is very dusty I'd go round with the henry as well. (DPM) with joints well lapped and folded. Outside ground should be. CS Flooring. or as a sandwich membrane in base concrete or between the base concrete and screed. As a rough guide, laying a conventional sand/cement screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. Also there MUSt be a DPM under the screed to stop any substrate moisture coming up from underneath as a result of heating. TF. I am happy to employ gs guy to do pipe and install boiler but don't want to be calling the guy several times months appart, hence the attempt to make. 5m x 100m, 2m x 100m, and 2m x 50m. Hi guys. P. f) whether there is an effective dpm within or under the existing base; g) whether the screed is to provide the wearing surface, if so, the type and intensity of traffic to be expected; h) if not a wearing surface, the type and thickness of the finished flooring to be applied; i) type of underfloor heating (if any) to be used; applications are suitable for bonded topping screeds. The damp proof membrane (DPM), normally 1200g polythene or radon barrier, should be laid over the blinding,So not convinced glue down is right. Reinforcing concrete. How to Damp proof a floor and walls using synthaproof as a damp proof membrane is shown in this tutorial. •Suitable for use on cement/sand screeds containing water based under floor heating systems •Apply ARDITEX NA direct without priming JUNE 2019 (SUPERSEDES MARCH 2018) PRODUCT DATA SHEET (43) V. Mapeproof One Coat is not recommended for heated subfloors where wood floor coverings are to be installed. • To provide a wearing surface. Depends where the UFH pipes are. Flowable liquid floor screed suitable for applying up to a depth of. Our Liquid DPM can be used on walls under a render to create a flexible waterproof layer. AFAIK - PIR insulation boards need have a DPM under them to protect the board. In this scenario, a rigid foam insulation is usual, and as you’d want the same U value in the roof, we need the same thickness of insulation. (See FeRFA Guidance Note No. Consideration should be given to applying the DPM to the top of the slab, as the installation and moisture sensitive internal finishes are then protected from any residual moisture in the concrete. studs 63mm x 38mm at maximum 600mm centres. I would guess, that a standard mix was used, as that would be cheapest, so could assume 1mm per day, but that`s why a test would be needed. Mastic Asphalt – this is the earliest form of liquid DPM and is usually laid on the top of another membrane or a fibreglass surface. This will leave bitumen (ironically) glue residue behind which is a problem to remove I believe - and must be completely gone. Block and beam grout/slurry wetness. The purpose of DPM. Alan Jackson - Commercial Manager UK and Ireland - Gypsol. It has to breath to survive. Damp proof membranes (DPM) A DPM should be a minimum thickness of 1200g polythene and linked to the DPC with a minimum 100mm overlap. The Epoxy DPM 5kg is supplied in two 2. 14 m-1 P/A and use of edging insulation. Instead of a membrane, use a foam underlayment material which will keep the wood from touching the screed directly (avoiding any moisture transfer) but which will also allow the screed to breathe and thus dry over time. It’s primarily designed for brushing onto concrete floors and fine concrete screeds. There are great benefits to be had by utilising calcium sulphate screeds, mainly due to their ability to be pumped, therefore reducing the time that screeders need to be on site. If the applied DPM is still very tacky, this1. Screed & Insulation. With the number of planning applications for basement extensions rising by 183% according to research by Halifax, tilers need to be aware. I intend to lay 75mm PIR. - Polythene membrane (DPM) - Insulation (rigid board type) - Concrete slab min. would it beneficial to change the floor structure to incorporate circa 250mm of eps insulation under the concrete slab, instead of the 150mm pir above. Generally fairly high grade stuff too. 1 or just a bit less. The installation of a liquid damp proof membrane is a vital stage in the construction process, for both new builds and refurbishment work where a structural DPM may be missing or damaged, or where residual construction moisture is present in the floor. the advice by these two posters is absolutely incorrect, if your RH% is above 75% you absolutely need a surface dpm and dual screed the test takes 72 hours to take though, depending on size the price you were quoted is reasonable (surprisingly from Carpetright), there are certain BS you must follow for correctly preparing a sub. Country. Thin screed to level old concrete floor. 9% screeds been down since February. All tiles and sand cement screed removed and last remaining suspect area. 50 Ex VAT £21. insulation 60mm. PermaSEAL Liquid DPM can also be applied to concrete floors below screeds. A laminate wll be glued onto that. Wet underfloor heating. SikaBond® Rapid DPM is a single part moisture curing polyurethane. Discussion in ' Builders' Talk ' started by Liz990, Feb 21, 2021 . #2. Trusted Trader, said safety must be a priority after a flood. The dpm has added to the problem by removing any bonding capabilities within the floor screed. 8 Apr 2013. 5m height allowed under permitted development as possible. Reaction score. What the DPM is attached to can fail. Laying new floor - needs DPM? dunroving Posts: 1,881 Forumite. 4) at a thickness of 3" inches The guidelines state that a damp proof membrane that is placed under the flooring should be around 1200 gauge and constructed of polyethene. Refer to manufacturer’s guidelines. I've dug down and exposed part of the DPM sheet under the slab so I'm happy using trade plan, turbo then renovation screed. screed. Visqueen ECO Membrane Data Sheet. Dig it all up (Its possibly up to 50mm thick) Then lay DPM/Visqueen sheets tanked up the walls and lay new concrete or use an epoxy liquid DPM tanked up the walls and lay a deep base screed. The DPM should: have sealed laps of at least 300mm wide link with wall DPCs to form an impervious barrier to. #1. B. Yes. Use 1000 gauge or thicker – ideal for this is the polyethylene use for the DPM under your concrete subfloor. Damp Proof Membranes. Use polyethylene sheeting to create a waterproof membrane to ensure that there is no leakage of the screed when it is pumped in wet. Onto the concrete. Sand / Cement screeds must have a moisture reading of less than 75% RH before work. by sound of it you could latex that floor 3x with the amount of screed you intend buying and you can't prime under a dpm or dpm over a water based screed. DPM under block and beam. They can feel wobbly when you walk on them but you get to the point when you can't get them any better and each give you walk on them or lift them you end up going around in circles. The lower sand ratio means a higher ratio of cement, which gives a stronger mix. 99 Inc Vat. New-build install: £50 to £75 per square metre.