9% screeds been down since February. 24 Jul 2009. Hello, hoping someone can help. They can therefore be laid under the DPM (the DPM is still necessary to prevent. Using this latex based damp proof paint as a damp p. The rest of the floor will be as follows (top down); flooring. The builder wants to apply a DPM to the top of the slab before it is dry. 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. Mapeproof One Coat is not recommended for heated subfloors where wood floor coverings are to be installed. 28 Sandiwch damp-proof membrane. Also there MUSt be a DPM under the screed to stop any substrate moisture coming up from underneath as a result of heating. Care must be taken to a) ensure there are no holes or tears in the sheet that could allow. DPM is usually below the concrete, then the insulation, then a polythene sheet to stop the insulation floating as the screed is poured. You now have a 'swimming. Mot1 Sand/hardcore sub base. 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. Property is mid 1960s, solid ground floor. 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). 19 Mar 2011. We provide a range of solutions including DPM screed, flooring primers and more! We are also radon barrier suppliers, making us perfect for all your needs! Call: 0330 223 2364 ; Email: estimating@cscscreeding. ← Installation of rigid floor insulation on ground floor concrete substrates to receive screed. Relative Humidity: The moisture content or relative humidity of the atmosphere plays is a major factor that affects the drying time of the screed. g. 00. 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. Can anyone advise me if this needs to be completely dried out before put the screed down? I have exposed part of the slab by removing th insulation and peeling back the upper dpm and this has slowly drie over the week but the dpm is keeping the wet in where its stil. Thanks for the reply. ) • Floating (used to enable installation of thermal or impact sound insulation). if there is insulation also under the screed i. 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 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. #2. It has excellent adhesion to. Hi All, I'm purchasing a new build and want to put Amtico Spacia down throughout the downstairs. A water based is more likely the screed itself will blow as it cant take moisture at all, so it would be the 1st thing to blow. 5sqm has blown. you need to dig up the old concrete then lay a couple inches of sharp sand. Our Liquid DPM can be used on walls under a render to create a flexible waterproof layer. Pro-Screed Gold is moisture tolerant and can be used under and over DPM’s. So, as money's too tight to mention round here, I replaced the leaking door with a cheap UPVc one. The subfloor. 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. 001 Ardex Australia 201550mm insulation would be better than nothing be it under screed or timber. Issues to be taken into account include: installation. Should I lap DPM under or over Dpc then celotex, then another DPM lapped up the wall with 25mm up stands. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. 17) DPM under slab. This will. Thanks, Gastines3, FreeBear, and gwynlas! Well, I called a damp proofing guy in, he had a look said if it was him he would put in a screed at least 2 inches high and concrete outside. i'm you have gathered by now, you havn't left enough depth to do this. 100 hardcore, 50mm builder's sand to blind, 1200 gauge DPM, 70mm insulation (Celotex, Kingspan, etc. . The DPM (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. 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. What should normally happen is the inner course should be removed to concrete slab level. It is not. The following week, I got high moisture readings (90% plus) in several places on the concrete flooring, from a hygrohood I borrowed from a local flooring company. 14 assuming 0. He has sealed the joints as well so hopefully they won't squeak. 12 Sep 2015. Customer asked me how did they stop rising damp before the Dpm sheet was used and it made me think ( that hurt ) . 1, your new concrete will need drying time, approx 1 month for every inch, then a DPM is required. The outcoming drain will have the dpm taped to it all the way around. 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. Renovation property: £135 to £185 per square metre. heating installations with cementious screeds provided a temperature of 27°C is not exceeded. The surface should be of sufficient quality and. In any case, it’s best to use a specialist to avoid damaging the floorboards themselves. Liquid DPMs gave the best protection but were more expensive. You also should have removed the vinyl tiles before priming and screeding. either way, as the other posts say, you would be better screeding which will also take out any irregularities in the concrete. POLYTHENE DPM & VAPOUR BARRIERS. The screed layer is damaged by damp, and is easily disturbed/crumbled. With the number of planning applications for basement extensions rising by 183% according to research by Halifax, tilers need to be aware. 5m height allowed under permitted development as possible. The tiler can then latex or screed over the DPM. e. 1200 Gauge DPMs should be used when a floor is direct to the ground. 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. do I still need a DPM under that insulation? it is internal and sitting on a structural slab that is wrapped in DPM externally. Prime and reapply , then screed to level and tile. 22) Steel. For traditional screed, the usual total will fall within the range £18. #1. We always remove the masonry below allowing the floor screed to have a bit of 'meat' to help overcome the differential movement. The excellent adhesive qualities and quick drying time of Drybase Liquid-Applied DPM make it extremely versatile. You can lay a fast track DPM (damp proof membrane) if your new concrete has had 2/3 weeks drying time. Flexible - easy to detail and install on site. Some slate or concrete board should then bridge the cavity gap. Fax: 0800 270 7368. How to Damp proof a floor and walls using synthaproof as a damp proof membrane is shown in this tutorial. 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. The extension is yanked and the architect has spec'd Marley Dampseal for the dpm which will sit under 60mm of Kingspan and 75 mm of screed. JB Flooring Well-Known Member. Self levelling compound is often known as floor screed or floor levelling compound and is essential for creating an even floor surface in preparation for upper flooring layers. 2. #5. DPM's must be carefully protected where folded up the perimeter walls, and lapped under the DPC particularly at door openings. I am assuming its asphalt with a bitumen top layer, 10-15mm thick. Then use the correct screed. 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. The basic screed construction for under floor heating systems generally follows the ‘floating’ screed construction, where a Damp Proof Membrane (DPM) and tacker insulation panels are laid over the. I'm not saying this is the best thing to use. studs 63mm x 38mm at maximum 600mm centres. insulation 60mm. On a job that’s had anhydrite screed pumped in, using a Wolff gm200 moisture meter readings in parts are 99. above the slab I am having a screed to cover the UFH pipes. Screed. "Your insurance company should be able to instruct property drying. 5m) It will have 50mm insulation boards on top of it, followed by 18mm/22mm. 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. blocking/nogging for support of plasterboard 43mm x 38mm. #2. not a good idea man. Easy Handling & Installation. Figure 2: Concrete floor cast into rebate in foundation wall. I'm looking for opinions on the best self leveling screed to use on my slightly wonky concrete garage floor. Our Epoxy DPM can be used on concrete floors and fine concrete screeds, of not less than 50mm thick in the case of un-bonded screeds. Unless there is an easy way. Perfect for new builds and refurbishment projects, our range of floor insulation products include optimum peformance OPTIM-R Vacuum Insulation Panels (VIPs) with an insulating performance up to five times better than commonly used insulation materials, and. The liquid membrane forms a strong seal and makes a permeable layer to enable moisture to evaporate off. But others are direct to earth, brick, rubble what ever. Country. It's a complete lack of knowledge on your floorlayers part or possibly just a carpet fitter trying his luck. To add to this, when we bought the house about 6 months ago the existing felt roof (on the extension) had a gaping hole that was letting rain water. 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. 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. 1 Feb 2010. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. In the attached photo I have removed poorly laid DPM and insulation boards with a view to starting again. ; Stiffness: Concrete floors generally possesses adequate prudery & does not parry under the applied load which result in generating problems in non-structural elements, e. It may be applied onto either a solid in-situ concrete ground floor slab or onto a precast concrete floor unit. . Staffordshire. Visqueen are recommending we don't use Ecomembrane but instead use Visqueen Vapour Barrier if we have a DPM under a screed with UFH heating, because it doesn't have folds in it and this helps prevent cracks in the screed. The insulation level and fabric of the building should always be factored into an underfloor. 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. You are talking about a solid concrete floor which has to be on load bearing stable ground. Ideal for use where there is no functioning structural DPM (common in older properties). Our costs are ballpark averages – get a local tradesperson to quote now. A latex based screed isnt as affected by moisture/damp as a water based is. Step 3: Lay the watertight membrane. This could have been avoided by building the membrane on to the inner leaf only and protecting it with a 100mm DPC, or by protecting the wide horizontal DPC with an. Cement screed. 27 Dec 2020. This reduces the risk of harmful interstitial condensation by ensuring that any moisture within the. I'd like to change our tiled dining room room floor to a carpeted floor with underfloor heating. 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. Outside ground should be. 5 ratio of cement to sharp sand. Hello, I have noticed some funny things going on under the floor of our recently bought house, which was originally built in 1905. DPM’s can be applied to either a suitable blinding layer under the slab or internally to the top of the slab. It is usually abbreviated to 'DPC', and in most buildings less than 30 years old, it consists of a DPM, which is a Damp Proof Membrane, an impermeable layer of material, most often a polyethylene or bitumen-polymer, that is laid in the bedding joint between two courses of bricks. Answered 22nd Aug 2016. Guidance on how to install insulation between a floor screed with Kingspan Kooltherm K103 Floorboard. I would say the screed was. 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. Discussion in ' Builders' Talk ' started by barnjules, Jan 30, 2017 . Installing floor insulation boards above the concrete slab and below the floor screed is an effective insulation method particularly for underfloor heating systems where the underfloor heating pipes are contained within the floor screed. celotex goes UNDER concrete. The floor originally had a carpet laid on top of the tiles, when I lifted it nothing felt, looked or smelled damp. A typical beam and block application would have beam and block 100mm depth, insulation between 150-300mm and screed 65-75, a total floor depth of between 325-475 which could require as many as three extra rows of brickwork. The work falls under building regs part L and you need minimum 70mm PIR insulation. I recently had a new boiler installed and new radiators fitted, and the plumber has cut the old copper. This can include timber floors, tiles, laminate flooring and carpet. To avoid damage to the insulation layer and the dpm it is necessary to take care in tipping, spreading and compacting wet concrete or screed. Just lay a couple of good thick beads on the dpm and stick it to the wall. Our team of highly experienced technical experts are always on hand to provide the highest level of support and advice to our customers. Care must be taken to a) ensure there are no holes or tears in the sheet that could allow. As a rough guide, laying a conventional sand/cement screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. An expansion gap may be necessary around the edge of the floor finish in screed or. The mat seperates the UFH and the (normally) floor tiles, and allows them to expand at different rates, so stops the tiles cracking. you can then lay your celotex or similar then concrete then screed or dpm concrete insulation screed . 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. with the concrete but the insulation. Fast drying screed cost. Two coats will provide protection up to a maximum hygrometer reading of 95% RH. All other sheet membranes can be used with unbonded toppings. 2. 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. Yes. Notch7. All modern buildings have what is known as a Damp Proof Course. However the chance that the floor tiles or adhesive can release fibres and become respirable when disturbed is very low. This barrier is intended to stop moisture passing from one to the other. Changed mate!constructed as a separate concrete (Figure 2) or concrete masonry (Figure 3) perimeter foundation wall with the slab laid later. Damp Proof Membranes. The. I don't understand how to bridge the cavity under the bifold without filling the cavity or compromising on structural strength. 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. 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. (DPM) with joints well lapped and folded. Fibreglass 1. Therfore putting foil faced boards under screed is a waste of time and is the principle reason kingspan make tissue faced boards. DPM sheets should be overlapped by at least 300mm. VCLs prevent excess moisture entering a wall’s cavity, behind the insulation. F. 5kg multi chamber bags. Below Floor Screed 1. 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. Because we were laying Karndean Flooring to a new extension we needed to check the % RH(relative humidity) of the concrete with a hygrometer. Yes it is a small breach on regs but would be up to building control to decide. Use 1000 gauge or thicker – ideal for this is the polyethylene use for the DPM under your concrete subfloor. If the property is 200 years old it won't have a DPM under the concrete slab so its sitting direct on. You can usually achieve this with at least 100mm of good quality foam insulation or 150mm of mineral wool insulation, but this figure will vary depending on the make-up and size of your. Firstly, there was no need to use a liquid dpm if you used underlay with a built in vapour barrier. 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. The advantages are the relatively low price of about £12 per square metre in combination with also relatively low installation costs of £8 – £12 per sqm as well as the high load- bearing capacity of cement screed. £20 per m2. Tramex reading at the time of vinyl removal was 3-4+. Uses/Subfloors:If you have under floor heating, you can use it to dry the screed 7 days after installation and the additional depth, (up to 65mm), becomes less important, But you’re still wasting money on screed you don’t need. 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. So the floor has been there for 70. FlexiDry said: Yes laying the screed direct onto insulation is standard practise for a floating floor. 20 mm thickness should do it and im looking for the. or email. 5m x 100m, 2m x 100m, and 2m x 50m. If DPM ok then. 3 Oct 2004. The membrane is manufactured in standard 125mu, 250mu, and 300mu thickness and in roll sizes of 1. Discussion in ' Builders' Talk ' started by Liz990, Feb 21, 2021 . framing joints secured with not less than 2 nails per joint. LKAB Minerals +44 (0) 7966 651006. The damp proof membrane (DPM), normally 1200g polythene or radon barrier, should be laid over the blinding,So not convinced glue down is right. It stops around 10mm away from the internal walls in all rooms. AN INTRODUCTION TO. 4. Ideally there should be a fully working dpm under the main concrete slab but where this does not exist or where the time for the slab to dry out sufficiently is longer than the building programme can permit, a dpm can be included either above or below the screed. Curing Under Polythene 12 hrs 12 hrs Drying Time To Receive Finishes - from removal of curing polythene sheet 50mm thickness and 50% RH. There’s also ridges from where the tiles used to be. 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. Sealing a patch of DPM around its edge to the old is easy, just use silicone goo. 23 Dec 2020. For guidance on using DPM One Coat Membrane with screed products refer to the individual ScreedPro Data sheet concerned. Then mix up the high performance stuff as that is fibred and can be taken to a feather edge. J. 5m2 at 1mm thickness 1. m10 cement based levelling and wearing screeds 160 m12 resin flooring 163 m13 calcium sulfate based screeds 165 m20a plastered coatings 166 m20b rendered and roughcast coatings 169 m21 insulation with rendered finish 172 m40 stone, quarry and ceramic tiling or mosaic 173 m42 wood block composition block and mosaic parquet flooring 1763. This DPM is a ‘thick’ plastic sheet mostly 1000 – 1200 gauge polythene material. Jabfloor 70 has a nominal 1% compression value of 21kPa (2. A floor screed is usually a cementitious material made from a 1:3 or 1:4. First, divide the floor up. C. The Concrete slab will have been placed in January so it's had about 8 months to dry out. doors. 1. Temporary protectionI had part of a 9" wall knocked down for a doorway. hallbeck New Member. Diagram B38 - DPM lapping under DPC for thickness of inner leaf. Since that period I've take out the bitumen screed/dpm and been on the concrete slab since about mid February/March. 16) Concrete slab 300mm. UZIN has the right floor damp proof membranes for damp proofing floors. link with wall DPCs to form an impervious barrier to prevent moisture reaching the interior of the dwelling. . Fintan has been involved extensively in a deep energy retrofit of a property to the Enerphit standard in the west. Renovation property: £60 to £85 per square metre. CSC screeding was very efficient that they screeded our floor in under 4 hours (around 91sqm) with the help of the Mixamate. TB243. 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. Maybe better to use a fibre based leveling compound instead, like Granfix Fibreflex 50 or similar. ARDEX DPM 1 C may be used if; 1. At the time of building the extension, due to new footings for structural walls to hold steels, drainage installed and the existing floor within the house showing signs of damp where the bitumen DPM had failed under floorboards nailed to the screed, I took the decision to remove all the floors, and oversited the whole house. I am the Managing Director of the Multi-Award Winning Speed Screed. USES For priming, consolidating and sealing of: Absorbent and non-absorbent sub-floors, consolidat-ing weak cement screed and isolation of old adhesive residues. is that do-able? if so, can I just run the DPM 1 course above DPC? it's too late to tuck. DPM sheets should be overlapped by at least 300mm. There will be a damp-proof membrane under the insulation and possibly a second membrane on top, depending on the type of screed. Types of Liquid DPM. A Vapour Control Layer, or VCL for short, is a plastic layer that restricts the movement of warm, moist air from inside a property into the fabric of the building. Currently, the central heating pipes and mains water pipes are all buried below the damp proof membrane, under the screed. There needs to be one under the beams that rest on the internal wall. Country. 8 Oct 2015 #4 So you have a concrete slab laid on a DPM, and later a 65mm sand & cement screed laid on the Extn. 150mm PIR insulation. Out of the 7sqm of floor i guess about 1. When sand-blinded, BAL DPM allows tiling onto difficult substrates such as steel. 17 May 2010. Our Epoxy DPM can be used on concrete floors and fine concrete screeds, of not less than 50mm thick in the case of un-bonded screeds. I am putting down a 22mm engineered oak floor so will use an underlay without a dpm. 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). 5kN/m2. 034 W/mK, and is used to insulate inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring. Like x 2; Agree x 2; List (You. Material. framing joints secured with not less than 2 nails per joint. However to get BC off your back you can use a epoxy DPM and sand scatter it before it sets. 25W/m 2 K to meet with building regulations, even if you didn’t plan to. Ball and Co. This told us tha. Insulation Below A Floor Screed. Damp proof membranes (DPMs) can be used to help resolve damp issues which already exist or to avoid damp or moisture problems in the future. I'm thinking dpm under the floor board and then 3:1 motar under the DPM to bed on the blocks. 100mm c35 concrete with mesh. 0. 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. 4 Screed. 25 Apr 2010. first of all check your existing floor is perfectly level, if not then forget the freeflowing screed as it will not level up with the existing floor. carpet, tiles etc. 3k. The plan was to lay American Black Walnut but the hallway floor was not level. £ 49. For reference, screed is a thin layer of concrete poured over a floor base. Location. So he said to put the insulation on top of the slab. As a waterproofer, BAL DPM is an easy two-coat system when used with BAL Self-Adhesives Butyl Tape in corners and junctions. The screed manufacturer agrees that their screed can receive an epoxy DPM. top of my concrete slab was about 50mm below DPC, I finished with battens and floorboards. Option 1 is clearly cheaper but as long as it takes a screed floor (says it does) and gets signed off by. Do you need DPM under garage floor? Solid floor The existing concrete floor can be used as a base, however a new damp proof membrane (DPM). Mapeproof One Coat can be used with underfloor heating systems providing the system has been fully commissioned as per BS8203 2009, Section 3, 3. Damp proof membranes (DPM) A DPM should be a minimum thickness of 1200g polythene and linked to the DPC with a minimum 100mm overlap. "Document any damage for insurance purposes. Trusted Trader, said safety must be a priority after a flood. £14 per m2. – the UK’s leading manufacturer of flooring adhesives and floor preparation products for the contract flooring industry. (This is assuming its a slab insulation. Answered 18th Aug 2020. There is a concrete slab in place with a DPM underneath. Hence we always say DONT apply a surface dpm to a subfloor subject to rising damp. The advice of a structural engineer should be sought for any exceptional point loads in the design of the floor. Seems fine so far. Labour costs. If under the screed this is normally a polythene dpm so the screed is then an. 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. Suitable for use with underfloor heating and for encapsulating electric cable undertile heating systems. 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. . Guarantees the early laying of all floorcoverings. As with the Kooltherm installation, start by ensuring a clean and level surface. Temporary protection should be given As proven in this Celotex Floor Insulation Guide, Celotex insulation is a versatile and effective flooring insulant. Energy Efficiency: Concrete floors generally possesses lofty thermal mass & this may be. Which way would you go, 1000 gauge plastic under slab OR liquid dpm between slab and screed? renovateduk, Jul 17, 2009 #3. 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. My work will be (in order of layers): 1) DPM 1000 gauge with joints taped with Polythene joint tape. Slightly below floor level are two layers of polythene membrane with a layer of floor levelling screed to make up to floor level. the DPM and new floor can then go on top of this. Insulation is a crucial consideration for UFH. Wet underfloor heating. This barrier is intended to stop moisture passing from one to the other. They can be used under resin screed finishes and are applied in thinner sections than standard cement screeds. Then a primer like the one you have at 4-1 then if needed another coat at 2-1. Walkable in 6 hours. #1. 45sqm to supply and fit. 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. This should be laid on a bedding material such as screed which doesn’t damage the sheet and has fully sealed joints. so FBall seems the way to go). Use a thick bed adhesive unless your competent to use screed, it takes skill and practice to create a flat floor. 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. Vac up any loose sand once it's set and then tile. if your DPM were above the concrete, the uFH would be heating a large damp lump of concrete. The DPM should: have sealed laps of at least 300mm wide. We've just had our garage converted and our builders have laid a screed floor. I intend to consult BC but would like to educate myself before I speak with them Thanks in advance. Was looking to do liquid DPM sandwich with fball 1200/F77/1200 (or NA/1cDPM/NA but that’s costing another 30% more. weberfloor DPM can be applied on to concrete or cement based screed surfaces with a. I think this is too expensive, so got a quote of another supplier of £2565 plus any potential floor preparation, with latex screen costing £13 /sqm or a feather finish at £2. Complete range, complete solution. At its deepest it’s 150mm, what I’m stuck with is the builders trying to push on with the job.