As a waterproofer, BAL DPM is an easy two-coat system when used with BAL Self-Adhesives Butyl Tape in corners and junctions. You will need to tear the lot up. 5mm Polyflor . Use screed on top of a concrete base to give your floor a level and smooth finish. J. "Document any damage for insurance purposes. Reinforcement is required when you’re concreting areas that will be subjected to heavy loads, such as garages and car parks. Country. 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. Types of Liquid DPM. I intend to lay 75mm PIR. 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. Curing under polythene 12 hrs 12 hrs Drying time to receive finishes - from removal of curing polythene sheet 50mm thickness and 50% RH. All waxes or sealers must be removed, and patching/leveling or embossing must be brought to a flatness of 3/16” in 10’. +44 (0) 333 202 6800. Use a thick bed adhesive unless your competent to use screed, it takes skill and practice to create a flat floor. Your privacy. Discussion in ' Builders' Talk ' started by barnjules, Jan 30, 2017 . The plan was to lay American Black Walnut but the hallway floor was not level. 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. 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. Ideal for use in shower areas where screeds are laid to falls incorporating a damp proof membrane. Epoxy DPM itself (the actual product epoxy) wont fail once set. C. There is a membrane underneath the concrete slab which has been poured and it comes up and meets the dpc. Checkatrade offers the following guide: Electric underfloor heating cost. 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. PermaSEAL Liquid DPM can also be applied to concrete floors below screeds. I would say the screed was. Figure 3: Concrete masonry foundation wall and concrete floor. The specific liquid DPM system will depend on the type of substrate or screed. DPMs on top of the slab, i. 13) Polypropylene. Prime and reapply , then screed to level and tile. carpet, tiles etc. Guide Underfloor heating A guide for house builders NF71 NHBC Guide to Underfloor Heating 2nd draft RH. 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. Give it a good wipe with a damp cloth and let it dry before you start. I always put the Celotex under the slab to ensure that it doesn't deteriorate between laying it down and screeding. "Remove water with pumps or buckets and contact your insurance company straight away. Mapeproof One Coat can be used with underfloor heating systems providing the system has been fully commissioned as per BS8203 2009, Section 3, 3. If the property is 200 years old it won't have a DPM under the concrete slab so its sitting direct on. The liquid membrane forms a strong seal and makes a permeable layer to enable moisture to evaporate off. 0113 2455450 sales@rawlinspaints. 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. Why is a. concrete slab. 5. However the tiler should apply a Primer before screeding such as StopGap P141. Can be used over underfloor heating. 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. Any advance on laying 75mm kingspan directly on existing screed with DPM beneath, then laying 18mm T&G moisture resistant chipboard. 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. I am assuming its asphalt with a bitumen top layer, 10-15mm thick. They can be used under resin screed finishes and are applied in thinner sections than standard cement screeds. Flexible - easy to detail and install on site. The screed layer is damaged by damp, and is easily disturbed/crumbled. 8mm2 at 6mm 1. Beam and block floors may need a levelling screed or grouting to ensure base level. Then the lamiante has trapped this water in creating the sweat. It's joining onto the garage I'm converting so the whole floor is getting built up with polythene DPM,. 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. 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. 1200 Gauge DPMs should be used when a floor is direct to the ground. Hello, I have noticed some funny things going on under the floor of our recently bought house, which was originally built in 1905. Alan Jackson - Commercial Manager UK and Ireland - Gypsol. At the junction of wall and floor the membrane overlaps the damp-proof course in the wall. com. As a rough guide, laying a conventional sand/cement screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. 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. It is not. Fast drying screed cost. You adjust the concrete slab to let your. Reinforcing concrete. 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. The dpm has added to the problem by removing any bonding capabilities within the floor screed. 27 Dec 2020. 6. Then use the correct screed. Hoping the power of the Screwfix forum can help with a totally baffling problem we are having with our new extension. 50 /sqm. 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. This barrier is intended to stop moisture passing from one to the other. These tiles have failed as some are missing/ some broken/ the bitumen broken down, meaning the DPM has failed, hence allowing the water through. Solid floor insulation –screed finish: Per m 2: £70: £90: £80: Labour: Per day: £180: £250: £215:. With the number of planning applications for basement extensions rising by 183% according to research by Halifax, tilers need to be aware. blocking/nogging for support of plasterboard 43mm x 38mm. Moisture in the base will impede the drying of the screed. 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. A few months have passed since then and is now on average 2. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. Ideally with a screed pump. 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. 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. DPM, Celotex, 1000 gauge poly, 100-150mm concrete with or without reinforcement, 50-80mm screed. 5mm = 2. 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. My DPM was these tiles that were bitumnned/black jacked to the floor. Using this latex based damp proof paint as a damp p. £12 - £16 per m2. Eventually I will rip out the old floor and replace it but I would like to understand (as much as possible) what is going on under it without taking it off. Floor board overlaps new screed by 50mm so is supported by new screed on inside edge. Do you need DPM under screed? What DPM is Required? If the hygrometer reading comes back above 75% relative. A suitable gauge damp proof membrane (DPM) and thermal insulation must be provided. 034 W/mK, and is used to insulate inverted roofs, basements, car park decks, and heavy-duty commercial, industrial and cold store flooring. Yes. Two coats will provide protection up to a maximum hygrometer reading of 95% RH. you can then lay your celotex or similar then concrete then screed or dpm concrete insulation screed . Walkable in 6 hours. The polyethene slip membrane installed over the insulation must be overlapped and sealed to prevent loss of screed. Temporary protectionI had part of a 9" wall knocked down for a doorway. Location. Replacing over half of your floor will mean you’ll have to insulate to at least 0. The flooring that’s going down is polyflor safety flooring it’s. Flowable liquid floor screed suitable for applying up to a depth of. I recently had a new boiler installed and new radiators fitted, and the plumber has cut the old copper. T ·Öà 4 ·Öò 8 ·Ñ• 2, Jun 15, 2007. Roger Kenworthy on 2021-08-13 17:59:40: Question:Durability: A befittingly developed floor screed will outlast the else modules of the building. 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. hence my suggestion that this dpc should lap up and over to join the dpm (under the insulation and screed), which in turn laps with a second higher dpc beneath. 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. blocking/nogging for support of plasterboard 43mm x 38mm. 19)Cement. 1 Feb 2010. Suitable for most construction damp proofing requirements. The same larger hole after I cut back some of the sandy concrete. above the slab I am having a screed to cover the UFH pipes. Visqueen 2000 gauge Polythene - 12. Then mix up the high performance stuff as that is fibred and can be taken to a feather edge. Capital Valley Plastics Ltd Damp-Proof Membrane Black 1200ga 25m x 4m (47163) (55) compare. 9. First, divide the floor up. Hull. 3 Oct 2004. The polythene damp proof membrane (DPM) – generally a 1200 gauge- can now be rolled out into place ensuring the perimeter abutments are adequately covered. 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. The floor make up is compaced hard core, 125mm concrete, dpm, 100mm insulation, 75mm concrete screed ( polished and heated). 11 Protection against heat, and BS 8204 Part 1 2003, Section 6. But others are direct to earth, brick, rubble what ever. 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. The rest of the floor will be as follows (top down); flooring. The idea is that you are to prevent any screed material from falling down any joints and coming into contact with the cold slab. 3k. i'n not farmiliar with wickes dpm and the primer used for professional (if you like) screeds is neoprene. 5mt x 4mt rolls | £ 56. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. 11. Used the primer neat as guidelines suggested. . so FBall seems the way to go). Under ambient conditions, PALACE 1-COAT DPM is ready to receive a smoothing compound as soon as 4 - 5 hours after application. #3. 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. the DPM and new floor can then go on top of this. Because we were laying Karndean Flooring to a new extension we needed to check the % RH(relative humidity) of the concrete with a hygrometer. Renovation property: £135 to £185 per square metre. Be very careful by rushing. The insulation level and fabric of the building should always be factored into an underfloor. Liquid DPMs gave the best protection but were more expensive. There is a small section along the chimney where. #1. The outcoming drain will have the dpm taped to it all the way around. #2. 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. #5. If there is an operational DPM beneath the concrete you don't need one on top. Fit a damp proof membrane as above, then lay a separation layer. They can therefore be laid under the DPM (the DPM is still necessary to prevent. . If the applied DPM is still very tacky, this1. 21) Timber block. This barrier is intended to stop moisture passing from one to the other. Unbonded Sand and Cement Screed Minimum Thicknesshelppppppppppppppppppppppppp just had to quote for screed flooring. now what i know of screeding is very little but i can do a good job i have used in the past chicken wire under floor insulation, slurry coats on concrete etc but the guy who wants the job doing is going on about a barrier around. hours for Ceramics. 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. If modified screed is used you can get down to 55mm. This will give calculated u-value of 0. Price: £4. framing joints secured with not less than 2 nails per joint. Pre screeding, you lay the DPM, install the insulation sheets and create vertical upstands of insulation block around the outside perimeter of the wall. Contractor wants to paint Sika Primer MD on top of the self leveling compound. We converted our garage and building control are insisting I install a DPM over the screed (even though the DPM runs under the concrete raft foundation of the house). Misinformed on this as he had put a dpm under the chipboard. Bostik Screedmaster Rapid DPM is a ready for use; one part, water-based damp proof membrane. 100mm thick (can be heated) - Levelling screed (as required: self levelling compound, sand/cement screed etc) - Flooring, e. sandwiched under the screed, were also common and usually in liquid form, e. 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. 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. 65mm Screed. 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. It is a thermally effective solution that is equally efficient in concrete floors, beam and block floors, and suspended timber floors. ) • Floating (used to enable installation of thermal or impact sound insulation). California Country. The dpm needs to be clean and dry. The purpose of DPM. Applying Damp Proof Membranes. It's a complete lack of knowledge on your floorlayers part or possibly just a carpet fitter trying his luck. It stops around 10mm away from the internal walls in all rooms. Slightly below floor level are two layers of polythene membrane with a layer of floor levelling screed to make up to floor level. Produced from Recycled Material. i'n not farmiliar with wickes dpm and the primer used for professional (if you like) screeds is neoprene. screed thickness. Only one coat though. The vinyl that was laid bubbled up, so contractor removed it. 4 Apr 2017. Made from a combination of sand, cement and water, usually in a sand/cement mix ratio of anywhere between 3:1 and 5:1. As a waterproofer, BAL DPM is an easy two-coat system when used with BAL Self-Adhesives Butyl Tape in corners and junctions. When stripping the bathroom, the area under the bath tub was bare concrete, lower than the rest of the "black" floor throughout the property. Discussion in ' Builders' Talk ' started by Liz990, Feb 21, 2021 . It is advisable to have a minimum of 100mm insulation covered with 60-80mm screed. Developed to suppress residual construction moisture in cementitious subfloors including power floated concrete and sand/cement screeds. or email. 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 (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. if your DPM were above the concrete, the uFH would be heating a large damp lump of concrete. 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. The oversite is then constructed internally along with polythene DPM, insulation and floor screed etc. Mine is below the concrete. Issues to be taken into account include: installation. I would think a strip out and start again would be your best option, you should consider where/why there is water evident before. The correct installation of polythene DPM, rigid insulation and separating layers are highly important to the. Deleted member 25896, Feb 2, 2021 #5. Can be used as a Damp Proof. However the tiler should apply a Primer before screeding such as StopGap P141. The option of 50mm insulation between battens is appealing. Don't think it will make much difference tbh, if you go the timber route use 22mm plywood instead of chipboard though. DPM sheets should be overlapped by at least 300mm. B. 4 so you have around 1. 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. flooringman Well-Known Member. 5m x 100m, 2m x 100m, and 2m x 50m. Insulation will then go on top and the screed layer would go over the whole lot. 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. 3. There is a concrete slab in place with a DPM underneath. 1, your new concrete will need drying time, approx 1 month for every inch, then a DPM is required. No mention of reinforced concrete screed. Location. DPM over a new underfloor heated screed, the heating system must be turned off 48 hours before application. 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. Registered Office: 6 Acre Close, Rustington, West Sussex BN16 3PG. I was then able to put in a dpm and a hefty layer of cellotex and then screed to the level of the house. It still might not have a DPM under the floor. Unless there is an easy way. DPM’s must be carefully protected where folded up the perimeter walls, and lapped under the DPC particularly at door openings. The best example of insulated floor thickness is 100mm (insulation) + 60mm (screed) + 20mm (floor tiles+adhesive). ARDEX DPM 1 C may be used if; 1. The DPM we use does not cancel all moisture out as this will end up. 4. Brian McNaughton & Son Ltd. Alan Jackson - Commercial Manager UK and Ireland - Gypsol. The guy doing it tried to compensate by using more adhesive and most of the wood has. 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. How to install vacuum insulation panels below a floor screed. Posted July 28, 2021. The DPM should extend up the external foundation walls to meet. This self leveling concrete’s use of latex. 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. This barrier is intended to stop moisture passing from one to the other. I've read that you shouldn't install DPM under SPC flooring as it can affect how it clicks together 3. The dpm is extended and taped around this opening. Note though that this will raise the floor level by 75-100mm (depending on the insulation). That seems to be the recommended practice but I'm not sure how many bother with the one on top. This is resorted to only under the duress of severe time constraint. Our self levelling compound, or floor screed, is available in a wide range of varieties for a multitude of floor installation applications. 3) 50mm - Screed with Concrete Fibres, on top of the insulation boards. applications are suitable for bonded topping screeds. (This is assuming its a slab insulation. 300 dries very hard Bitumen is soft so not compatible. #1 CGN Screwfix Select andyscotland said: ↑ The concrete slab I poured for my utility room extension is slightly uneven - a small dip into the centre. So, as money's too tight to mention round here, I replaced the leaking door with a cheap UPVc one. Checkatrade offers the following guide: Electric underfloor heating cost. The tiler can then latex or screed over the DPM. Country. hot bitumen, or cold bitumen in solution. Curing Under Polythene 12 h 12 h Isocrete K-Screed (Heavy Duty) COMPRESSIVE STRENGTH (28 DAYS) BS EN 13892-2 >30 N/mm2 BRE TEST CATEGORY BS 8204-1 Category A. Laying new floor - needs DPM? dunroving Posts: 1,881 Forumite. 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). 5sqm has blown. Use polyethylene sheeting to create a waterproof membrane to ensure that there is no leakage of the screed when it is pumped in wet. 5m) It will have 50mm insulation boards on top of it, followed by 18mm/22mm. The Epoxy DPM 5kg is supplied in two 2. 30 Jun 2023. If its not right. 2 of the internal walls in the older building will be left as bare stone,. 1. Find. So latex one its more likely the addy will be affected. £14 per m2. . Like x 2; Agree x 2; List (You. Can be used as a Damp Proof Membrane on sub-floors not under hydrostatic pressure. 19 Mar 2011. Hull. You'll also need to take the dpm up the walls as well. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. framing joints secured with not less than 2 nails per joint. Country. DPM Membranes for Concrete Floors A range of high quality DPM membranes from Capital Valley Plastics, designed for use with solid concrete slabs. A Damp Proof Membrane or DPM is a waterproof barrier that’s introduced between your sub floor and your wood floor. 2. The guidelines state that a damp proof membrane that is placed under the flooring should be around 1200 gauge and constructed of polyethene. Buy Now. Ie work down from FFL. For bonded screeds, M-Bond Extra epoxy resin combined DPM and bonding agent may beToday, new solid floors are far more substantial, typically comprising 150mm of compacted hardcore, 50mm of sand, a polythene sheet DPM, 100mm of concrete, then around 100mm of insulation plus a 60mm screed — in total, more than 450mm thick. I intend to consult BC but would like to educate myself before I speak with them Thanks in advance. 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. is that do-able? if so, can I just run the DPM 1 course above DPC? it's too late to tuck. POLYTHENE DPM & VAPOUR BARRIERS. Size is 4m x 4m. Ltd. Manchester • Member since 5 Jun 2015 • 64 jobs, 95% positive feedback. We are in the process of having an extension built. 21 Sep 2016. dthobhani; 18 Mar 2011; Floors, Stairs and Lofts; Replies 2 Views 1K. This reduces the risk of harmful interstitial condensation by ensuring that any moisture within the. Our costs are ballpark averages – get a local tradesperson to quote now. 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. Mapeproof One Coat is not recommended for heated subfloors where wood floor coverings are to be installed. #7. I was hoping to use a recycled content DPM. DPM’s can be applied to either a suitable blinding layer under the slab or internally to the top of the slab. Visqueen EcoMembrane DPM. 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. Water under tiles. 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. 8 Can you put DPM under. The problem is by the time we insulate, screed and lay the flooring we will be above the dpc& membrane level by 4 inches. 50mm C&S (1:4) screed towelled smooth. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. 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. The floor originally had a carpet laid on top of the tiles, when I lifted it nothing felt, looked or smelled damp. 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. Top. The membrane is manufactured in standard 125mu, 250mu, and 300mu thickness and in roll sizes of 1. Location. These black DPMs can also be used with underfloor heating - under normal operating conditions this will not adversely affect the membrane. Small domestic areas that are going to have carpet, wood or synthetic floors as the final surface are ideal to use in conjunction with. 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. 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. Sealing a patch of DPM around its edge to the old is easy, just use silicone goo. This will leave bitumen (ironically) glue residue behind which is a problem to remove I believe - and must be completely gone. Many can be used over a variety of existing uneven substrates, using gravity to allow the latex mixture to self-level. F. studs 63mm x 38mm at maximum 600mm centres. CS Flooring. 1200g DPM will be fine. Telephone: 0800 270 7837. heated levelling screeds. New-build install: £50 to £75 per square metre. 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. celotex goes UNDER concrete. from a purely technical point of view a screed should always be divorced from the substrate by means of an operational DPM. 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. We could scrape up the tiles and start again. rogerk101 likes this. As a rough guide, laying conventional screed costs around £15/m2, increasing by around £5/m2 when delivered ready-mixed. 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). Country. 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. DPM’s can be applied to either a suitable blinding layer under the slab or internally to the top of the slab. For technical support please call. P. Property is mid 1960s, solid ground floor. Then a DPM on top to avoid them floating in the screed. For the best results, we recommend leaving it to cure for 28 days. studs 63mm x 38mm at maximum 600mm centres. Diagram B39 - Proper sealing. All tiles and sand cement screed removed and last remaining suspect area. Block and beam grout/slurry wetness. Mark El-Kadhi New Member. What is liquid DPM? Liquid DPM is a system that is used. 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. 001 Ardex Australia 2015 Bulding regs would require 100mm insulation and 70mm reinforced screed for this. 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. This seems to have been used in abundance before the original screed was put down. 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. I am putting down a 22mm engineered oak floor so will use an underlay without a dpm. 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. . #1.