Try it free. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn,. 21. • To provide a wearing surface. if no dpm I would blackjack 2 coats on. screed finish over the insulation to match existing floor levels. Reinforcement is required when you’re concreting areas that will be subjected to heavy loads, such as garages and car parks. Property is mid 1960s, solid ground floor. This is done to maintain energy efficiency and prevent. Country. Pumped Anhydrite Screeds. When sand-blinded, BAL DPM allows tiling onto difficult substrates such as steel. royaloakcarpentry Senior Member. Top. blocking/nogging for support of plasterboard 43mm x 38mm. 28. Can be used over underfloor heating. Norfolk. 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. The screed manufacturer agrees that their screed can receive an epoxy DPM. This generally takes 1-2 days, depending on the thickness of the floor screed. Energy Efficiency: Concrete floors generally possesses lofty thermal mass & this may be. Depends where the UFH pipes are. 3k. #5. We are in the process of having an extension built. Is this okay? Or does this present a real risk of corrosion of the frame in the future?that's rising damp mate, need to dig up subfloor new concrete base, dpm leave 30 days then screed and surface membrane that should help fix the problem. Guarantees the early laying of all floorcoverings. I would also gripfill under the plate to supplement the fixings if it were screed. Im not quite sure where my DPC should be going. Vac up any loose sand once it's set and then tile. When sand-blinded, BAL DPM allows tiling onto difficult substrates such as steel. 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. The idea is that you are to prevent any screed material from falling down any joints and coming into contact with the cold slab. 2. 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. 15) DPM under screed. The best example of insulated floor thickness is 100mm (insulation) + 60mm (screed) + 20mm (floor tiles+adhesive). 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. Complete range, complete solution. The floor originally had a carpet laid on top of the tiles, when I lifted it nothing felt, looked or smelled damp. Temporary protection should be given As proven in this Celotex Floor Insulation Guide, Celotex insulation is a versatile and effective flooring insulant. Step 3: Lay the watertight membrane. 25W/m 2 K to meet with building regulations, even if you didn’t plan to. Acknowledgement : The Concrete Society. Produced from Recycled Material. You will need to tear the lot up. do I still need a DPM under that insulation? it is internal and sitting on a structural slab that is wrapped in DPM externally. Once the DPM is applied you need a laytex screed, so your adhesive and karndean stick to it. PermaSEAL Liquid DPM can also be applied to concrete floors below screeds. It is advisable to incorporate a light mesh within the raft for reinforcement. 6 March 2017 at 8:04PM edited 6 March 2017 at 8:59PM. Contractor wants to paint Sika Primer MD on top of the self leveling compound. 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). DPMs on top of the slab, i. fix battens to subfloor - I can't raise the floor height with battens on the screed, but I could lift and remove the 50mm screed layer, fix 50mm battens at 400mm centres direct to the concrete slab, and then boards fixed on top of the battens. Flowable liquid floor screed suitable for applying up to a depth of. . Epoxy DPM itself (the actual product epoxy) wont fail once set. Sunny Hampshire. Then a DPM on top to avoid them floating in the screed. 11 Protection against heat, and BS 8204 Part 1 2003, Section 6. New-build install: £50 to £75 per square metre. Capital Valley Plastics Ltd Damp-Proof Membrane Black 1200ga 25m x 4m (47163) (55) compare. I am assuming its asphalt with a bitumen top layer, 10-15mm thick. so FBall seems the way to go). I would think a strip out and start again would be your best option, you should consider where/why there is water evident before. Non-structural floor screeds shall be adequate for the location and intended use, and provide a suitable background for floor finishes. No need for double DPM. The DPM should: have sealed laps of at least 300mm wide link with wall DPCs to form an impervious barrier to. 100mm **concrete base*. #5. Effectively, a damp proof membrane (DPM) is used to create a barrier between a concrete (or screed) subfloor and a wood floor. 4 Screed. AFAIK - PIR insulation boards need have a DPM under them to protect the board. British Standard (8204:1) says minimum 65mm for domestic floating. 6. co. This barrier is intended to stop moisture passing from one to the other. What should normally happen is the inner course should be removed to concrete slab level. 6 March 2017 at 8:04PM edited 6 March 2017 at 8:59PM. If you are using a final floor finish which will be fixed to the screed’s surface using an adhesive then you will need to lightly sand the laitance off the surface of the screed before using a compatible primer and adhesive. Ltd. The only way to tell properly, is to carry out a proper test. 34. 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. Insulation is laid on the concrete and covered with a screed. This is a solvent, water free, epoxy resin and moisture tolerant curing agent that allows for immediate installation of moisture sensitive floor finishes onto concrete and. What you don't want to do, with a DPM under the screed, is create a moisture trap - which a second DPM would do. The. If there was no dpm I would suggest a uniformal distribution across the whole floor. Developer has quoted £3744 for approx. Installation systems for tiling and natural stone. VAT £ 0. UFH Pipwork. Jabfloor 70 has a nominal 1% compression value of 21kPa (2. Your builder or yourself should have laid dpm under the dpc course on top of the hardcore Base laid on soft building sand . Floor under carpet marked with chalk for wet areas. 0113 2455450 sales@rawlinspaints. 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. 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. from a purely technical point of view a screed should always be divorced from the substrate by means of an operational DPM. 25 Apr 2010. 4 Apr 2017. O and the Answer to Mapei and Uzin is no. 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. For unbonded and floating screeds, a DPM may be specified between the base slab and the screed. UZIN has the right floor damp proof membranes for damp proofing floors. Warm water underfloor heating. The builder wants to apply a DPM to the top of the slab before it is dry. 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. 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. DPM is normally used in floors. 0. As a waterproofer, BAL DPM is an easy two-coat system when used with BAL Self-Adhesives Butyl Tape in corners and junctions. i'n not farmiliar with wickes dpm and the primer used for professional (if you like) screeds is neoprene. 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. 29 per m², £42. So I have a concrete floor in the kitchen (concrete - DPM - 50mm screed), knocked through into the outside toilet which just had soil floor. It’s only to stop the screed running under the insulation. I could put the dpm under the concrete which would be as effective. 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. 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. Roger Kenworthy on 2021-08-13 17:59:40: Question:Durability: A befittingly developed floor screed will outlast the else modules of the building. Can anyone help me with the DPM under a stud partition? What's the usual way of putting it down when you're dividing a room. Our Liquid DPM can be used on walls under a render to create a flexible waterproof layer. Curing Under Polythene 12 hrs 12 hrs Drying Time To Receive Finishes - from removal of curing polythene sheet 50mm thickness and 50% RH. DPM Membranes for Concrete Floors A range of high quality DPM membranes from Capital Valley Plastics, designed for use with solid concrete slabs. 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. Insulate under the floor using the crawl space underneath. I moved into my new build nearly 2 months ago now and am having quite a few issues. Polycote DPM Primer is a superb twin pack high-performance epoxy coating that. What do think? What if we're pouring one of these strong self. 001 Ardex Australia 2015 Bulding regs would require 100mm insulation and 70mm reinforced screed for this. Our team of highly experienced technical experts are always on hand to provide the highest level of support and advice to our customers. 22 August 2019 at 10:27AM. 22) Steel. 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. 50 Ex VAT £21. Air bricks are. How to screed by hand step-by-step with our stars Luke and Lee who are at the top of their game and Luke is only 18 years old, very impressive. steve have you checked the level of all of the concrete floor. We are one of the leading manufacturers of advanced barrier technologies and design-based solutions for specifiers, contractors and builders merchants throughout the UK and Europe, you can count on Visqueen for product quality. DPM sheets should be overlapped by at least 300mm. The 'vapour barrier' attached to your underlay will only protect your floor from a slab reading 75% RH or less. Ie work down from FFL. 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). If there is an operational DPM beneath the concrete you don't need one on top. Yes run the dpm up the wall to connect wall dpc with floor dpm. £20 per m2. sandwiched under the screed, were also common and usually in liquid form, e. If you don't allow the screed to dry properly, the moisture will be trapped within the screed potentially causing failure. Use polyethylene sheeting to create a waterproof membrane to ensure that there is no leakage of the screed when it is pumped in wet. 00. Some houses in early 70s don't have a DPM as I've found out over the years. If Under floor heating is used It is essential that the pipes are laid on. Country. POLYTHENE DPM & VAPOUR BARRIERS. This barrier is intended to stop moisture passing from one to the other. Do you know whether the fitter did any kind of damp proofing under/on top of the screed? And have you had any damp problems since then?Screeds – general. Greater thickness of screed may lead to a colder floor. Fax: 0800 270 7368. . 20 mm thickness should do it and im looking for the. However the tiler should apply a Primer before screeding such as StopGap P141. The flooring that’s going down is polyflor safety flooring it’s. Resin and cementitious floor finishes combining performance and design. Staffordshire. Then the lamiante has trapped this water in creating the sweat. . Bonded Screed Maximum Depth. Unbonded screeds are used either to install a damp proof membrane (dpm) between the base slab and the screed or where the base slab surface is unsuitable for a bonded screed due to problems such. Damp Proof Membranes. If the DPM is still wet you should have not tiled over. Anhydrite (liquid calcium sulphate) screeds offer a number of advantages: They’re not much dearer than ready-mix sand/cement, costing around £25/m3 (laid to a 50mm depth). Checkatrade offers the following guide: Electric underfloor heating cost. Information ARDEX DPM 1 C. Non-structural floor screeds shall be adequate for the location and intended use, and provide a suitable background for floor finishes. i'n not farmiliar with wickes dpm and the primer used for professional (if you like) screeds is neoprene. Checkatrade offers the following guide: Electric underfloor heating cost. I recently had a new boiler installed and new radiators fitted, and the plumber has cut the old copper. To remove the screed in order to relay a DPM is, in most cases, completely unrealistic and actually completely unnecessary. 5kg multi chamber bags. It is good practice to either fit another DPM or tape the insulation joints, when adding a screed on top of inso'. Country. 5m x 100m, 2m x 100m, and 2m x 50m. The subfloor. 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. Just lap the whole room up as normal, blobs of. Mine is below the concrete. I am assuming its asphalt with a bitumen top layer, 10-15mm thick. 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 concrete substrate before laying the heating elements of the under floor heating system. All waxes or sealers must be removed, and patching/leveling or embossing must be brought to a flatness of 3/16” in 10’. The DPM (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. 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. 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. For an excellent balance of. Suitable for most construction damp proofing requirements. 16) Concrete slab 300mm. Can you put DPM over screed? Liquid DPM is a system that is used over a base floor. Unless there is an easy way. 5 ratio of cement to sharp sand. Use 1000 gauge or thicker – ideal for this is the polyethylene use for the DPM under your concrete subfloor. 17) DPM under slab. A latex based screed isnt as affected by moisture/damp as a water based is. #2. Hi All come across this forum and would really appreciate some assistance. This will leave bitumen (ironically) glue residue behind which is a problem to remove I believe - and must be completely gone. 3. Walkable in 6 hours. This will. This barrier is intended to stop moisture passing from one to the other. Pumped anhydrite floor screeds are not much dearer than ready-mix sand/cement, costing around £25/m3 (laid. Guidance on how to install insulation between a floor screed with Kingspan Kooltherm K103 Floorboard. Bring the membrane up the surrounding foundation walls until it is just high enough to connect with or form the wall damp proof course. 20)Reinforced concrete floor. Flexible - easy to detail and install on site. +44 (0) 333 202 6800. Misinformed on this as he had put a dpm under the chipboard. Information ARDEX DPM 1 C. 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. Warm construction build-up would be: - Sand blinded sub-base. Anyway, my DPC/DPM seems to have been done wrong, but I just wanted to ask what I should do next to make it work. 24 h After curing of screedSANS 10400, Part J Floors (which is the SABS “deemed to satisfy” regs) states: “Ventilation of the subfloor space in suspended ground floors shall be provided by means of openings spaced not more than 2,4. 22 August 2019 at 10:27AM. It also looks like there could be polystyrene under the screed, this will be a barrier to damp coming from the ground. The minimum sand and cement screed thickness would be 40mm as defined by the British standard. 19)Cement. How to Damp proof a floor and walls using synthaproof as a damp proof membrane is shown in this tutorial. The floor make up is compaced hard core, 125mm concrete, dpm, 100mm insulation, 75mm concrete screed ( polished and heated). You must design out the (damp/thermal) vulnerabilities associated with raft type foundations as they can be a headache. Temporary protectionI had part of a 9" wall knocked down for a doorway. sandwiched under the screed, were also common and usually in liquid form, e. It is also recommended that light reinforcement be used. 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. The surface should be of sufficient quality and. Our Liquid DPM can be used on walls under a render to create a flexible waterproof layer. In these cases the insulation goes on top of the slab. The blockwork above the DPC will become saturated and cause damp problems within the extension, the skirting boards will rot and the mould will occur on the plaster. 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. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. 5sqm has blown. But this all begs the question of why the hallway is so wet. 21m2 1. The problem is by the time we insulate, screed and lay the flooring we will be above the dpc& membrane level by 4 inches. . Do you need DPM under screed? What DPM is Required? If the hygrometer reading comes back above 75% relative. adamhardy Member. screed (with UFH) 75mm. The position would vary in. hallbeck New Member. For guidance on using DPM One Coat Membrane with screed products refer to the individual ScreedPro Data sheet concerned. 5mm Polyflor . 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. Will prim t be okay as primer on top of turbo? Thanks PeteUnless designed otherwise, the minimum specification for all partitions should be: sill and head plates 63mm x 38mm. Should I lap DPM under or over Dpc then celotex, then another DPM lapped up the wall with 25mm up stands. The DPM should: have sealed laps of at least 300mm wide. He intended to stick the floor to the bitumen DPM. If modified screed is used you can get down to 55mm. Bostik Screedmaster Rapid DPM is a ready for use; one part, water-based damp proof membrane. 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. weberfloor DPM can be applied on to concrete or cement based screed surfaces with a. 00 per roll. 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 the. 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. Should I lap DPM under or over Dpc then celotex, then another DPM lapped up the wall with. In both cases the surface on which the dpm is laid needs to be as smooth as possible. Using this latex based damp proof paint as a damp p. floating construction then a second "slip". For under screed use: Must have from ground up: dpm (under subfloor in this case), insulation, plastic vapour check, sand-cement screed or fibre-concrete. Customer asked me how did they stop rising damp before the Dpm sheet was used and it made me think ( that hurt ) . you need to dig up the old concrete then lay a couple inches of sharp sand. LAY DAMP PROOF MEMBRANE. Curing under polythene 12 hrs 12 hrs Drying time to receive finishes - from removal of curing polythene sheet 50mm thickness and 50% RH. Yes it is a small breach on regs but would be up to building control to decide. 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. It stops around 10mm away from the internal walls in all rooms. #2. The DPM is tied into the internal leaf of masonry. The DPM should extend up the external foundation walls to meet. This told us tha. 5kN/m2. 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. rip some 18mm ply. If applying a screed to Drybase® Liquid-Applied DPM, the second coat can be used as a primer if the screed is applied while the second coat is still tacky. 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. Under ambient conditions, PALACE 1-COAT DPM is ready to receive a smoothing compound as soon as 4 - 5 hours after application. Prime and reapply , then screed to level and tile. So, as money's too tight to mention round here, I replaced the leaking door with a cheap UPVc one. Before screeding can commence the area to be screeded must be made watertight to prevent leakage. Contact Us. Other benefits. The company keeps abreast of market developments by. 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. Can be used as a Damp Proof Membrane on sub-floors not under hydrostatic pressure. Visqueen 2000 gauge Polythene - 12. If the DPM is still wet you should have not tiled over. The membrane is manufactured in standard 125mu, 250mu, and 300mu thickness and in roll sizes of 1. £51. Temporary protection should. New-build install: £120 to £135 per square metre. The subfloor in my house is a concrete slab with no DPM. 12 Sep 2015. It may be applied onto either a solid in-situ concrete ground floor slab or onto a precast concrete floor unit. 11. Drybase Liquid-Applied DPM should be used in situations where the final surface is going to be covered. 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. How to install vacuum insulation panels below a floor screed. Its an easy job to do yourself - also check Seconds & Co for PIR. For unbonded and floating screeds, a DPM may be specified between the base slab and the screed. #1. screed thickness. . DPMs on top of the slab, i. In the attached photo I have removed poorly laid DPM and insulation boards with a view to starting again. Pro-Screed Gold is suitable for application over most underfloor heating systems. 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. 4. Option 1 is clearly cheaper but as long as it takes a screed floor (says it does) and gets signed off by. Manchester • Member since 5 Jun 2015 • 64 jobs, 95% positive feedback. 12) Tiles glued. 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. An ARDEX Damp Proof Membrane will protect the floorcovering. Ideally with a screed pump. Then prime the marked out area. Liquid DPMs gave the best protection but were more expensive. framing joints secured with not less than 2 nails per joint. #1. TB243. Vac up any loose sand once it's set and then tile. 19 Mar 2011. The tiler can then latex or screed over the DPM. Suitable for use with underfloor heating and for encapsulating electric cable undertile heating systems. Ideal for use in shower areas where screeds are laid to falls incorporating a damp proof membrane. The polyethene slip membrane installed over the insulation must be overlapped and sealed to prevent loss of screed. Self levelling compound was laid straight on top of the concrete floor (with no primer). Many can be used over a variety of existing uneven substrates, using gravity to allow the latex mixture to self-level. No this is designed to be used under floor screeds, tiles, render or plaster. heating installations with cementious screeds provided a temperature of 27°C is not exceeded. This can include timber floors, tiles, laminate flooring and carpet. (See FeRFA Guidance Note No. Mot1 Sand/hardcore sub base. As a rough guide, laying a conventional sand/cement screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. Hi, just laying insulation on 1200g DPM and now looking for a cheap / simple VCL to lay on top of the insulation and under the screed. Do your slab as intended, single course of brickwork around the perimeter, then build your frame. There will be a damp-proof membrane under the insulation and possibly a second membrane on top, depending on the type of screed. Fit a damp proof membrane as above, then lay a separation layer. 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. Learn More Damp Proofing 15 Items DPM Handy Pack - 300mu 1200 gauge - 4m x 5m Rating: 2 £17. Definition of terms See full list on ecotileflooring. You also should have removed the vinyl tiles before priming and screeding. Based on a screed done in 1963 I’d say 95% there won’t be a effective damp proof membrane under it so a epoxy dpm should of been used like Ardex DPM1c. 5m2 at 1mm thickness 1. #Screeding #Sc. This is resorted to only under the duress of severe time constraint. Pumped anhydrite floor screeds are not much dearer than ready-mix sand/cement, costing around £25/m3 (laid to a 50mm depth). The Epoxy DPM 5kg is supplied in two 2. The 40mm between the joists is about 0. 4. I want to level my workshop floor. 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. 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. This barrier is intended to stop moisture passing from one to the other. Easy Handling & Installation. Ideally I don't want to screed the floor inside now as it will primarily be a workshop so I'm trying to retain as much of the 2. . As with the Kooltherm installation, start by ensuring a clean and level surface. USES For priming, consolidating and sealing of: Absorbent and non-absorbent sub-floors, consolidat-ing weak cement screed and isolation of old adhesive residues. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. 75mm pir but we have decided on 100. flooringman, Apr 7,. Apply ARDEX DPM 1 C to protect the floorcovering installation from residual construction moisture and ground bearing moisture. user contributions licensed under CC BY-SA. indd 2 08/08/2016 16:50:21DPM underneath and a plastic sheet on top to stop the screed getting between the insulation panels. Screed.