The DPM is tied into the internal leaf of masonry. Checkatrade offers the following guide: Electric underfloor heating cost. Country. Firstly, there was no need to use a liquid dpm if you used underlay with a built in vapour barrier. Can you put DPM over screed? Liquid DPM is a system that is used over a base floor. That about sums it up, but if your DPM is also serving as a radon barrier (even in a low risk area) the DPM should lap across the cavity (with a downstand) to seal the cavity from radon. above the slab I am having a screed to cover the UFH pipes. But others are direct to earth, brick, rubble what ever. The screed layer is damaged by damp, and is easily disturbed/crumbled. Just lap the whole room up as normal, blobs of. Covering it in denso tape and maybe putting some dpm over the top before screeding? Yes copper is best and lasts forever, but in this situation what would you do? So far I'm leaving towards plastic which makes like easier, less stress thinking that there are all those copper joints under the screed and underfloor heating. 45sqm to supply and fit. Preparation is key with these coatings and the substrate must be sufficiently clean and dry. When we stick any floor down to the sub floor, solid or engineered, we insist on installing a liquid DPM unless the existing is guaranteed to be 100% in tact. The screed manufacturer agrees that their screed can receive an epoxy DPM. Cushion Ultra Silver Wood 10m² Underlay: The best laminate underlay for damp protection. I was then able to put in a dpm and a hefty layer of cellotex and then screed to the level of the house. 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. Can you put DPM over screed? Liquid DPM is a system that is used over a base floor. 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. It is also recommended that light reinforcement be used. user contributions licensed under CC BY-SA. Damp Proof Membranes. (See FeRFA Guidance Note No. DPM, Celotex, 1000 gauge poly, 100-150mm concrete with or without reinforcement, 50-80mm screed. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. So latex one its more likely the addy will be affected. The water got under the DPM and wet the slab and blinding layer. . This barrier is intended to stop moisture passing from one to the other. Non-structural floor screeds shall be adequate for the location and intended use, and provide a suitable background for floor finishes. My query is regarding the floor insulation, damp proofing and screed. Renovation property: £135 to £185 per square metre. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. In addition to the damp proof membrane (normally a 1200-gauge polythene sheet below the insulation), a 500-gauge polythene VCL. T ·Öà 4 ·Öò 8 ·Ñ• 2, Jun 15, 2007. Scaffold boards should be used for barrowing and tipping concrete and screed and a light mesh of chicken wire can be used over separating layers or dpms over insulation under screeds as added protection. You can lay a fast track DPM (damp proof membrane) if your new concrete has had 2/3 weeks drying time. Hull. 2. It also looks like there could be polystyrene under the screed, this will be a barrier to damp coming from the ground. from a purely technical point of view a screed should always be divorced from the substrate by means of an operational DPM. Can be used over underfloor heating. 55mm of TS15 will impart around 1. I'd like to change our tiled dining room room floor to a carpeted floor with underfloor heating. All waxes or sealers must be removed, and patching/leveling or embossing must be brought to a flatness of 3/16” in 10’. Firstly, there was no need to use a liquid dpm if you used underlay with a built in vapour barrier. As an alternative to under concrete or surface damp-proof membranes a damp-proof membrane may be sandwiched between the site concrete and the floor screed, as illustrated in Fig. 5kg multi chamber bags. 16 Nov 2016. Fax: 0800 270 7368. 3. Effectively, a damp proof membrane (DPM) is used to create a barrier between a concrete (or screed) subfloor and a wood floor. USES For priming, consolidating and sealing of: Absorbent and non-absorbent sub-floors, consolidat-ing weak cement screed and isolation of old adhesive residues. 4. 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. . An ARDEX Damp Proof Membrane will protect the floorcovering. Curing under polythene 12 hrs 12 hrs Drying time to receive finishes - from removal of curing polythene sheet 50mm thickness and 50% RH. blocking/nogging for support of plasterboard 43mm x 38mm. It’s primarily designed for brushing onto concrete floors and fine concrete screeds. Where screed is laid on top of insulation, screed should have a minimum depth of 65mm. ARDEX DPM 1 C may be used if; 1. Self levelling compound was laid straight on top of the concrete floor (with no primer). 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. But this all begs the question of why the hallway is so wet. Our Liquid DPM can be used on walls under a render to create a flexible waterproof layer. #Screeding #Sc. 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. Under ambient conditions, PALACE 1-COAT DPM is ready to receive a smoothing compound as soon as 4 - 5 hours after application. – the UK’s leading manufacturer of flooring adhesives and floor preparation products for the contract flooring industry. The main drawback. Posted July 28, 2021. I'm looking for opinions on the best self leveling screed to use on my slightly wonky concrete garage floor. If the wall is very dusty I'd go round with the henry as well. Cutting open would void dpm so should be avoided. No this is designed to be used under floor screeds, tiles, render or plaster. weberfloor DPM is a two-component epoxy based chemical damp proof membrane that is capable of being applied in one coat, dependent upon the condition of the substrate and quality of workmanship to ensure full coverage is achieved at the required thickness. View complete answer on allthingsflooring. But on the basis of more insulation is better, consider fitting more and laying cupboard flooring on top, or on joists. Walkable in 6 hours. There are many proprietary screeds on the market and information about these can be obtained from the manufacturer. Once set, you can then apply your screed flooring to the DPM base. The bitumen adhesive also contained the same asbestos fibres. rip some 18mm ply. The oversite is then constructed internally along with polythene DPM, insulation and floor screed etc. 14 assuming 0. Any advance on laying 75mm kingspan directly on existing screed with DPM beneath, then laying 18mm T&G moisture resistant chipboard. Applying Damp Proof Membranes. A Damp Proof Membrane or DPM is a waterproof barrier that’s introduced between your sub floor and your wood floor. A section of the old screed layer has broken up around the edge of the patio door threshold. 12 Sep 2015. Like x 2; Agree x 2; List (You. Yes run the dpm up the wall to connect wall dpc with floor dpm. Do you need DPM under screed? What DPM is Required? If the hygrometer reading comes back above 75% relative. DPC and DPM are lapped together at this stage. Go for the application of a surface DPM; The third option is however quite expensive, and could turn out to be more expensive than the screed itself. below this liquid screed I am adding 50mm EPS100 to build up the depth (which reduces the thickness of the screed) and also to fix the UFH pipes to. 100 hardcore, 50mm builder's sand to blind, 1200 gauge DPM, 70mm insulation (Celotex, Kingspan, etc. If a screed such as A38 or Topcem was used, this can reduce the drying time, and with A38 this can be just one day. 4 Apr 2017. Contact Us. If you are getting up to the 50mm, you would question whether you want to use a smoothing product really just from an economic point of view,. 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. Or have you asked them can you install Surface DPM on a Wet subfloor that does still have a DPM under it? Don't confuse the TWO. floating construction then a second "slip". Could us a liquid dpm like Drybase (2 coats), then a sand/cement screed,with fibre reinforcment, 25mm is the minimum thickness for bonded screed, that's thin,might still crack, no need for primer with Drybase. of the screed should be checked by the Main Contractor. The liquid membrane forms a strong seal and makes a permeable layer to enable moisture to evaporate off. Pumped anhydrite floor screeds are not much dearer than ready-mix sand/cement, costing around £25/m3 (laid. 11 Protection against heat, and BS 8204 Part 1 2003, Section 6. Hello, hoping someone can help. Once set, you can then apply your screed flooring to the DPM base. do I still need a DPM under that insulation? it is internal and sitting on a structural slab that is wrapped in DPM externally. Installation systems for tiling and natural stone. The maximum depth you would use a smoothing compound would generally be around out 10mm, you can add aggregates, to bulk up the screed going up to 30, 40, 50+mm. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. 5kg multi chamber bags. Non-structural floor screeds shall be adequate for the location and intended use, and provide a suitable background for floor finishes. If there was no dpm I would suggest a uniformal distribution across the whole floor. All modern buildings have what is known as a Damp Proof Course. What do think? What if we're pouring one of these strong self. You adjust the concrete slab to let your. The guy doing it tried to compensate by using more adhesive and most of the wood has. 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. It originally had Marley tiles stuck down with bitumen 'glue', but many of them are missing and I will remove the rest. They are happy for the 25mm board to be laid on the screed, pipes clipped in then 9mm ply on top finally topped off with ceramics. Use a thick bed adhesive unless your competent to use screed, it takes skill and practice to create a flat floor. You are therefore at the edge of the joists capability. Use polyethylene sheeting to create a waterproof membrane to ensure that there is no leakage of the screed when it is pumped in wet. Hello, I have noticed some funny things going on under the floor of our recently bought house, which was originally built in 1905. Depends where the UFH pipes are. A poorly compacted, damaged or weak screed should be completely removed by mechanical means and reinstalled correctly. 1 Feb 2010. The screed will be only ~50 max (not yet dug any up). Then once the screed is dry use a liquid DPM such as F-Ball Stopgap F77. 3 Oct 2004. 23 Dec 2020. 9% screeds been down since February. If there is an operational DPM beneath the concrete you don't need one on top. 1 tonnes per m²), which is suitable under a 75mm screed in normal domestic situations. There is a small section along the chimney where. 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. I will be tiling over the screed so looking for the simplest option. Information ARDEX DPM 1 C. So he said to put the insulation on top of the slab. you then have a continuous damp couse not inportant if concrete above dpc level. Fig. All other sheet membranes can be used with unbonded toppings. (DPM) with joints well lapped and folded. the cut. 4. Insulation must be provided under their entire area to ensure compliance with the Building Regulations is achieved. 34 dpm under insulation and screed. 74 inc. With the power of hindsight I would have made the slab the same size as the structure so the bricks were flush with the edge then left enough DPM to run. 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. I don't understand how to bridge the cavity under the bifold without filling the cavity or compromising on structural strength. Pre screeding, you lay the DPM, install the insulation sheets and create vertical upstands of insulation block around the outside perimeter of the wall. Epoxy DPM itself (the actual product epoxy) wont fail once set. Reinforcement to Suspended Floor SlabsClick and buy N-Virol Superseal Plus Damp Proofing DPM Paint which an be used for several applications including damp walls, floors and on basement walls. below this liquid screed I am adding 50mm EPS100 to build up the depth (which reduces the thickness of the screed) and also to fix the UFH pipes to. If the DPM is still wet you should have not tiled over. Fit a damp proof membrane as above, then lay a separation layer. studs 63mm x 38mm at maximum 600mm centres. UZIN has the right floor damp proof membranes for damp proofing 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. Water under tiles. 5kg multi chamber bags. Mobile Sales: 07920 715745. A full sheet DPM is 250 microns (1000 gauge) thickness or above. 67. This will give calculated u-value of 0. 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. If you are just trying to take a hollow out get a long straight edge and use a marker pen to mark out the perimeter of the hollow. ) • Floating (used to enable installation of thermal or impact sound insulation). 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. Apply ARDEX DPM 1 C to protect the floorcovering installation from residual construction moisture and ground bearing moisture. The idea is that you are to prevent any screed material from falling down any joints and coming into contact with the cold slab. Its an easy job to do yourself - also check Seconds & Co for PIR. Bostik Screedmaster Rapid DPM is a ready for use; one part, water-based damp proof membrane. There is a membrane underneath the concrete slab which has been poured and it comes up and meets the dpc. High quality painting, plastering and drywalling tools. Complies with BS 8485:2015 + A1:2019 - industry standard for methane and carbon dioxide protection. Then prime the marked out area. Don't use a bitumen at all, you are correct eventually your screed will fail. 5sqm has blown. But what I dont understand is what to do to. Damp proof membranes (DPM) A DPM should be a minimum thickness of 1200g polythene and linked to the DPC with a minimum 100mm overlap. Jan 24, 2019. £12 - £16 per m2. 1200 Gauge DPMs should be used when a floor is direct to the ground. HYDRONIC UNDERFLOOR HEATING A CONCISE GUIDE FOR ARCHITECTS & SPECIFIERS ON PLANNING UNDERFLOOR HEATING SYSTEMS Introduction This guide is intended as a basic guide to the fundamentals of hydronic underfloor heating to assist specifiers to incorporate underfloor heating in their design. Checkatrade offers the following guide: Electric underfloor heating cost. New-build install: £50 to £75 per square metre. There needs to be one under the beams that rest on the internal wall. We have our sub concrete floor in, and there will be a 1200g dpm, then 100mm insulation, then another dpm and finally 65-70mm screed. . The damp proof membrane (DPM), normally 1200g polythene or radon barrier, should be laid over the blinding,So not convinced glue down is right. I would say the screed was. #2. Hi, I’m after some advice/suggestions regarding my floor…We’ve recently moved into a 60s house which has a screed floor, on top of a concrete base with no DPM. Out of the 7sqm of floor i guess about 1. Option 1 is clearly cheaper but as long as it takes a screed floor (says it does) and gets signed off by. The rest of the floor will be as follows (top down); flooring. Can be used as a Damp Proof. Curing Under Polythene 12 hrs 12 hrs Drying Time To Receive Finishes - from removal of curing polythene sheet 50mm thickness and 50% RH. An ARDEX Damp Proof Membrane will protect the floorcovering. There’s also ridges from where the tiles used to be. Discussion in ' Builders' Talk ' started by Liz990, Feb 21, 2021 . Complete product range for installation, renovation and maintenance of wood flooring. 27 Dec 2020. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. Renovation property: £60 to £85 per square metre. Country. What the DPM is attached to can fail. Give it a good wipe with a damp cloth and let it dry before you start. 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. If the DPM is still wet you should have not tiled over. DPC and DPM are lapped together at this stage. Sunny Hampshire. The surface should be of sufficient quality and. Express Liquid Screeds Limited. When it comes to the hearth I know that I need to have a constructional hearth at least 125mm thick that extends out 300mm in front of the stove. Then a primer like the one you have at 4-1 then if needed another coat at 2-1. 30 Jun 2023. 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. 10 Feb 2020. When I origianlly pulled it up it was damp under the bitumen screed/dpm around some cracks in the slab (guess trapped moisutre was trying to escape there), it dried in about 10-15 minuntes and has been done dry and. 10 Sep 2021. Cement screed. 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. 90 per pack | Buy now from UK Flooring Direct. 2m3). Damp Proof Membrane is intended for use within solid concrete floors to prevent the rise of moisture or damp through structure flooring. Bostik Screedmaster Rapid DPM is a ready for use; one part, water-based damp proof membrane. For an excellent balance of. For bonded screeds,4 weeks will depend on the depth - keep the screed as thin as possible - with wet UFH normally 50mm - any more will delay the drying time. The liquid membrane forms a strong seal and makes a permeable layer to enable moisture to evaporate off. top of my concrete slab was about 50mm below DPC, I finished with battens and floorboards. not bonded to the base – typically where a DPM is placed under the screed. Read more about changes to thermal elements 1 (in the 'External Walls' section)The removal leaves a surface the bonding agent can bond to, ensuring the screed does it’s job. Material. 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. 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). 300 dries very hard Bitumen is soft so not compatible. 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. Just lay a couple of good thick beads on the dpm and stick it to the wall. Produced from Recycled Material. Renovation property: £60 to £85 per square metre. 5m height allowed under permitted development as possible. 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. 1200g dpm. In both cases the surface on which the dpm is laid needs to be as smooth as possible. 20 mm thickness should do it and im looking for the. What should normally happen is the inner course should be removed to concrete slab level. bandejapaisa; 30 Jun 2023; Building; Replies 5 Views 1K. hallbeck, Jan 26, 2010 #5. The surface should be of sufficient quality and. Laying new floor - needs DPM? dunroving Posts: 1,881 Forumite. It is much easier to work on sections of the floor than try to achieve an even finish across the whole floor in one go. Drybase Liquid-Applied DPM should be used in situations where the final surface is going to be covered. #1. If you're laying Karndean over existing flooring, be sure it is properly prepared. Changed mate!constructed as a separate concrete (Figure 2) or concrete masonry (Figure 3) perimeter foundation wall with the slab laid later. "Turn off electricity and gas only if it’s safe to do so," he said. As a rough guide, laying a conventional sand/cement screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. On the other hand, a dpm on top of the new concrete will push all the moisture towards the walls, so you would have to incorporate the dpm into. screed (with UFH) 75mm. e. Renovation of more than 25 per cent of a solid or suspended floor involving the replacement of screed or a timber floor deck would have to meet the standards required by the building regulations Approved Documents. 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. Right based on those joist spacings and dimensions the joists should easily accept 1. 15) DPM under screed. Pre screeding, you lay the DPM, install the insulation sheets and create vertical upstands of insulation block around the outside perimeter of the wall. 9. The clips only pierce the thinner layer above the insulation, which is only really there to ensure an unbonded concrete/screed above. The concrete slab was usually 100 to 125mm thick. Hi I have fibreboard underlay in the instructions for the underlay it states if using this product on ground floor you should also use vapour barrier or damp proof membrane beneath the underlay. I want to level my workshop floor. 034 W/mK, and is used to insulate inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring. com. I was planning on putting 1200g DPM down, then 80mm celotex insulation (taped at joints), then 65mm screed (approx 1. UFH inside plastic polypanels 75mm screed (probably not liquid). For a self-levelling screed a system such as Flowcrete UK’s Hydraseal would be used. 2. Complete range, complete solution. Energy Efficiency: Concrete floors generally possesses lofty thermal mass & this may be. J. #3. The tiler can then latex or screed over the DPM. A standard sand/cement screed would need to be laid at a minimum depth of 65mm for a domestic property. P. It is important to ensure that a proper seal is achieved around all services. This told us tha. Visqueen 2000 gauge Polythene - 12. Wet underfloor heating installation cost. Screed above dpm. The option of 50mm insulation between battens is appealing. Diagram B39 - Proper sealing. However the tiler should apply a Primer before screeding such as StopGap P141. 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. Other benefits. Under Floor Heating; Screed Care; Testing; Tips; Blog; Contact; A Practical Guide to Screed Testing: What Do the Experts Say? Download. Our self levelling compound, or floor screed, is available in a wide range of varieties for a multitude of floor installation applications. 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. Ideal for use where there is no functioning structural DPM (common in older properties). The polythene damp proof membrane (DPM) – generally a 1200 gauge- can now be rolled out into place ensuring the perimeter abutments are adequately covered. DPM under block and beam. The DPM (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. It may well require the re cement to be removed, a liquid dmp used with dry sharp sand thrown on it before it dries, and then use a flexible self levelling screed. Diagram B38 - DPM lapping under DPC for thickness of inner leaf. Get it level then when it is dry and can screw through floor board into blocks. LKAB Minerals +44 (0) 7966 651006. PermaSEAL Liquid DPM can also be applied to concrete floors below screeds. The screed manufacturer agrees that their screed can receive an epoxy DPM. 250mu Polythene DPM is suitable for use as a damp proof membrane under screed floors. #1. Can be used as a Damp Proof Membrane on sub-floors not under hydrostatic pressure. xednim, Apr 6, 2019. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. Modified anhydrite screeds for use with UFH can now be installed as little as 35 mm deep with a 15 mm pipe in a domestic application. Applying Damp Proof Membranes. They can be used under resin screed finishes and are applied in thinner sections than standard cement screeds. 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. Warm water systems, such as those available at The Underfloor Heating Store, feature an array of pipes, laid just below the surface of your floor. The screed has water anyway, so a bit of ingress isnt an issue. Ie work down from FFL. DPM, Celotex, 1000 gauge poly, 100-150mm concrete with or without reinforcement, 50-80mm screed. 5mt x 4mt rolls | £ 56. DPM's must be carefully protected where folded up the perimeter walls, and lapped under the DPC particularly at door openings. The specific liquid DPM system will depend on the type of substrate or screed. The asphalt screed provides a membrane to the surface of the concrete floor preventing moisture within the constructional slab causing decay to the floor coverings. screed finish over the insulation to match existing floor levels. sandwiched under the screed, were also common and usually in liquid form, e. if your DPM were above the concrete, the uFH would be heating a large damp lump of concrete. Beam and block floors may need a levelling screed or grouting to ensure base level. You will need to tear the lot up. 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. I would also gripfill under the plate to supplement the fixings if it were screed. Out of the 7sqm of floor i guess about 1. We always remove the masonry below allowing the floor screed to have a bit of 'meat' to help overcome the differential movement. The old adhesive should of been removed. •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 heating must be switched off at least 48 hours before and after application Bostik Screedmaster One Coat DPM and Bostik Screedmaster One Coat Accelerator are both solvent free products and are suitable for use in all project workHow-to video with step-by-step instruction on how to apply liquid damp proofing, priming and then self leveling. 8). It's a small garden room with a 2 course brink plinth, DPC, and then timber sole plate. In order to prevent damp rising through the concrete floor and causing issues, a DPM should be used under all final floor types including wood flooring, laminate, vinyl and floor tiles. These tiles have failed as some are missing/ some broken/ the bitumen broken down, meaning the DPM has failed, hence allowing the water through. Can be used under a surface DPM Excellent flow characteristics Protein-free and low odour USES Bostik Screedmaster Flow is a two-part, protein and casein free, cementitious underlayment with improved flow for smoothing uneven floors prior to. applications are suitable for bonded topping screeds. 0113 2455450 sales@rawlinspaints. Spoke to makers of UFH system. Suitable for use with underfloor heating and for encapsulating electric cable undertile heating systems. - Polythene membrane (DPM) - Insulation (rigid board type) - Concrete slab min. screed over insulation. 6 March 2017 at 8:04PM edited 6 March 2017 at 8:59PM. C. Which way would you go, 1000 gauge plastic under slab OR liquid dpm between slab and screed? renovateduk, Jul 17, 2009 #3. The Epoxy DPM 5kg is supplied in two 2. someone suggested removing the blocks on the inside along the width of the bifold and screeding all the way to the brick course.