For unbonded and floating screeds, a DPM may be specified between the base slab and the screed. This barrier is intended to stop moisture passing from one to the other. 2. hallbeck New Member. The problem is by the time we insulate, screed and lay the flooring we will be above the dpc& membrane level by 4 inches. (DPM) with joints well lapped and folded. Country. An ARDEX Damp Proof Membrane will protect the floorcovering. 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. Greater thickness of screed may lead to a colder floor. All tiles and sand cement screed removed and last remaining suspect area. Prime and reapply , then screed to level and tile. This site contains a wealth of information on our extensive product range, along with a selection of videos demonstrating their application. #1. Below Floor Screed 1. blocking/nogging for support of plasterboard 43mm x 38mm. 4. Well, when I did exactly this on my lower retaining wall - a mere footandahalf high - I lined the back with DPM, the stuff you put under screed to seal yer floors from rising damp. 21. 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. 4 Apr 2017. Unless there is an easy way. To help determine the cost of a screed floor let’s look at the average prices people pay. 9% screeds been down since February. 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. This will allow the screed to. 5m2 at 1mm thickness 1. Currently, the central heating pipes and mains water pipes are all buried below the damp proof membrane, under the screed. The advice of a structural engineer should be sought for any exceptional point loads in the design of the floor. Some houses in early 70s don't have a DPM as I've found out over the years. Refer to manufacturer’s guidelines. Hi All, I'm purchasing a new build and want to put Amtico Spacia down throughout the downstairs. Issues to be taken into account include: installation. Insulate under the floor using the crawl space underneath. 19 Jul 2015. 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 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. take account of possible differential movement. 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. Diagram B39 - Proper sealing. Looking for best method to both level and damp proof the concrete, to then be covered with a thin layer of celotex, then engineered wood or laminate. It's joining onto the garage I'm converting so the whole floor is getting built up with polythene DPM,. Suitable for most construction damp proofing requirements. 1 or just a bit less. 16) Concrete slab 300mm. 17 May 2010. The DPM we use does not cancel all moisture out as this will end up. 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. This will leave bitumen (ironically) glue residue behind which is a problem to remove I believe - and must be completely gone. Temporary protection should be given As proven in this Celotex Floor Insulation Guide, Celotex insulation is a versatile and effective flooring insulant. The Epoxy DPM 5kg is supplied in two 2. 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. Use polyethylene sheeting to create a waterproof membrane to ensure that there is no leakage of the screed when it is pumped in wet. 9. royaloakcarpentry Senior Member. Discussion in ' Builders' Talk ' started by barnjules, Jan 30, 2017 . 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. Dig it all up (Its possibly up to 50mm thick) Then lay DPM/Visqueen sheets tanked up the walls and lay new concrete or use an epoxy liquid DPM tanked up the walls and lay a deep base screed. FlexiDry said: Yes laying the screed direct onto insulation is standard practise for a floating floor. He intended to stick the floor to the bitumen DPM. Brian shows how to correctly fit a Damp Proof Membrain - DPM in a new build houseLink to the T-Rex tape Website Http://bodgeitwithbri. The optimum thickness of a sand. 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. framing joints secured with not less than 2 nails per joint. Property is mid 1960s, solid ground floor. . Preparation is key with these coatings and the substrate must be sufficiently clean and dry. Under ambient conditions, PALACE 1-COAT DPM is ready to receive a smoothing compound as soon as 4 - 5 hours after application. 100mm thick (can be heated) - Levelling screed (as required: self levelling compound, sand/cement screed etc) - Flooring, e. It's a complete lack of knowledge on your floorlayers part or possibly just a carpet fitter trying his luck. Energy Efficiency: Concrete floors generally possesses lofty thermal mass & this may be. Ideally there should be suitable insulation below the underfloor heating pipe to resist the heat going downwards. Location. AN INTRODUCTION TO. #2. 5sqm has blown. 150mm PIR insulation. Had a look at the pics and IMO no dpm under the subfloor. Hull. (See FeRFA Guidance Note No. 001 Ardex Australia 201550mm insulation would be better than nothing be it under screed or timber. The water got under the DPM and wet the slab and blinding layer. #1. Its an easy job to do yourself - also check Seconds & Co for PIR. Ideal for use where there is no functioning structural DPM (common in older properties). Polycote DPM Primer is a superb twin pack high-performance epoxy coating that. 1 Feb 2010. Dig the oversite ground to whatever height allows your hardcore, insulation, blinding, slab,screed. #5. For this, a metal mesh standing with plastic pillars ( (feet) will be laid before the concrete is. Country. 3. 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. Laybond Screedmaster One Coat Liquid DPM 2 part solvent free epoxy surface damp proof membrane developed to. 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. Out of the 7sqm of floor i guess about 1. What is DPM under screed? Damp-proof membrane (often called DPM) is used in construction to prevent moisture from entering the building, usually through capillary action. 5mm = 2. 6 March 2017 at 8:04PM edited 6 March 2017 at 8:59PM. 22 August 2019 at 10:27AM. of the screed should be checked by the Main Contractor. 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. steve have you checked the level of all of the concrete floor. Can be used as a Damp Proof. Looking for best method to both level and damp proof the concrete, to then be covered with a thin layer of celotex, then engineered wood. I am the Managing Director of the Multi-Award Winning Speed Screed. C. The ground floor is wooden floor boards and there are 2 rooms I need to do. g. The DPM (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. heated levelling screeds. This barrier is intended to stop moisture passing from one to the other. Made from a combination of sand, cement and water, usually in a sand/cement mix ratio of anywhere between 3:1 and 5:1. You also mentioned that there are vinyl tiles over the floor. 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. Apply ARDEX DPM 1 C to protect the floorcovering installation from residual construction moisture and ground bearing moisture. with the concrete but the insulation. ), then 500 gauge plastic (or just use the leftover 1200 gauge DPM) then 100mm concrete slab. Then a DPM on top to avoid them floating in the screed. I am assuming its asphalt with a bitumen top layer, 10-15mm thick. Lay and level the concrete slab, allowing sufficient time to dry out, as per BS 8203. 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. 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. Then mix up the high performance stuff as that is fibred and can be taken to a feather edge. Pro-Screed Gold is suitable for application over most underfloor heating systems. Suitable for use with underfloor heating and for encapsulating electric cable undertile heating systems. Last autumn we knocked down an old conservatory and kitchen extension and built a new extension in the same place. #1. 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. not bonded to the base – typically where a DPM is placed under the screed. is that do-able? if so, can I just run the DPM 1 course above DPC? it's too late to tuck. 3. So I have a concrete floor in the kitchen (concrete - DPM - 50mm screed), knocked through into the outside toilet which just had soil floor. apparently some of the screeds had a cold or hot bitumen in or under them. I would think a strip out and start again would be your best option, you should consider where/why there is water evident before. Effectively, a damp proof membrane (DPM) is used to create a barrier between a concrete (or screed) subfloor and a wood floor. Thin screed to level old concrete floor. 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. you can then lay your celotex or similar then concrete then screed or dpm concrete insulation screed . I don't understand how to bridge the cavity under the bifold without filling the cavity or compromising on structural strength. Now we realise this cannot be done and are trying to get out of a fix. Yes it is a small breach on regs but would be up to building control to decide. "Your insurance company should be able to instruct property drying. Hoping the power of the Screwfix forum can help with a totally baffling problem we are having with our new extension. framing joints secured with not less than 2 nails per joint. 5mm Polyflor . Like a lot of houses of that age, the ground floor is bitumen/asphalt over a concrete screed. The DPM should come up in an upstand and tie into the DPC on the. 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. top of my concrete slab was about 50mm below DPC, I finished with battens and floorboards. The same larger hole after I cut back some of the sandy concrete. Insulation Below A Floor Screed. 8). Use 1000 gauge or thicker – ideal for this is the polyethylene use for the DPM under your concrete subfloor. The. Using pin m/m's on a concrete or s&c screed floor needs experience - more important is what is the composition of the slab or the in-situ screed and if there is an actual DPM below the floor. Non-structural floor screeds shall be adequate for the location and intended use, and provide a suitable background for floor finishes. 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. Overlap it and tape it with duct tape or 100mm pvc tape. 3) 50mm - Screed with Concrete Fibres, on top of the insulation boards. This will allow the screed to bond to the dpm. When stripping the bathroom, the area under the bath tub was bare concrete, lower than the rest of the "black" floor throughout the property. You are therefore at the edge of the joists capability. Applying Damp Proof Membranes. Ideal for use where there is no functioning structural DPM (common in older properties). There’s also ridges from where the tiles used to be. . if no dpm I would blackjack 2 coats on. Also there is no DPM under the slab. 5mt x 4mt rolls | £ 56. Cement screed. • To provide a wearing surface. Lay the dp membrane over the concrete slab and lapped over the brickwork. If the concrete in-fill is low, after patching the DPM, putting the screed on it will cause the centre of the DPM to drop and pull away at your new seal around its. The purpose of DPM. I. DPM (1200 gauge visqueen) Old Concrete Slab. 2 Feb 2010. You adjust the concrete slab to let your. What’s the difference between a DPC and DPM? The DPM dries to form a permeable membrane that allows moisture to evaporate off in a controlled way. 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. . Answered 18th Aug 2020. Brian McNaughton & Son Ltd. 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. You will need to tear the lot up. bandejapaisa; 30 Jun 2023; Building; Replies 5 Views 1K. Self levelling compound was laid straight on top of the concrete floor (with no primer). Then use the correct screed. 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. If I did my external one at the same height then the outside floor height would sit very low so presumably I can put the external one at the same level as. Wet underfloor heating. This is done to maintain energy efficiency and prevent. I'd like to change our tiled dining room room floor to a carpeted floor with underfloor heating. Changed mate!constructed as a separate concrete (Figure 2) or concrete masonry (Figure 3) perimeter foundation wall with the slab laid later. If you don't allow the screed to dry properly, the moisture will be trapped within the screed potentially causing failure. also alot of the insulation manufacturers specify a 500/1000 gauge membrane between the insulation and the screed inkpad, Aug 6, 2009 #7. Celotex PIR’s closed-cell, moisture-resistant composition helps to prevent water ingress. My question is thoughts on floor layout. Maybe better to use a fibre based leveling compound instead, like Granfix Fibreflex 50 or similar. Use screed on top of a concrete base to give your floor a level and smooth finish. 6 March 2017 at 8:04PM edited 6 March 2017 at 8:59PM. Guide Underfloor heating A guide for house builders NF71 NHBC Guide to Underfloor Heating 2nd draft RH. Cement screed is the most commonly installed type of screed and is suitable for both interior and exterior surfaces. Step 3: Lay the watertight membrane. Any existing floor screeds, coatings or adhesive residues. 10 Feb 2020. Ground-bearing concrete floor slabs should be protected against ground moisture by providing a continuous damp proof membrane (DPM). An ARDEX Damp Proof Membrane will protect the floorcovering. DPM, Celotex, 1000 gauge poly, 100-150mm concrete with or without reinforcement, 50-80mm screed. 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. Also, even with 80mm screed directly over Celotex the sab can feel a bit "hollow". B. jeds. 18) Bricks. This should be laid on a bedding material such as screed which doesn’t damage the sheet and has fully sealed joints. 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. 4 Screed. I was then able to put in a dpm and a hefty layer of cellotex and then screed to the level of the house. Temporary protectionI had part of a 9" wall knocked down for a doorway. Firstly, there was no need to use a liquid dpm if you used underlay with a built in vapour barrier. I am putting down a 22mm engineered oak floor so will use an underlay without a dpm. • GG300 – 300kPa. A suitable gauge damp proof membrane (DPM) and thermal insulation must be provided. Figure 3: Concrete masonry foundation wall and concrete floor. SikaBond® Rapid DPM is a single part moisture curing polyurethane. Installation systems for tiling and natural stone. This self leveling concrete’s use of latex. 50mm C&S (1:4) screed towelled smooth. jonathanc Guest. The purpose of DPM. As nod mentioned, your DPC will actually be the first layer of DPM you put down bef ore the insulation. Based on a screed done in 1963 I’d say 95% there won’t be a effective damp proof membrane under it so a. Also there MUSt be a DPM under the screed to stop any substrate moisture coming up from underneath as a result of heating. Concrete & Sand/Cement Screeds Concrete and sand/cement screeds must be dry and any laitance or surface treatments removed. Renovation property: £135 to £185 per square metre. However to get BC off your back you can use a epoxy DPM and sand scatter it before it sets. 30 Jun 2023. When this is down I will then lay more sand or light concrete mix up to the level of the old screed or just below, then let this dry and then apply about 3 coats of bitumin floor paint. It has to breath to survive. £14 per m2. 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. 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. Looking for a FLAT membrane as I am told the creases you get when you unfold 4m wide DPM / polythene from a 1m roll can cause cracks (plus its a real pain to lay). Replacing over half of your floor will mean you’ll have to insulate to at least 0. • GG500 – 500kPa. 100 hardcore, 50mm builder's sand to blind, 1200 gauge DPM, 70mm insulation (Celotex, Kingspan, etc. Reinforcement is required when you’re concreting areas that will be subjected to heavy loads, such as garages and car parks. 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. For reference, screed is a thin layer of concrete poured over a floor base. The DPM is tied into the internal leaf of masonry. 1200 Gauge DPMs should be used when a floor is direct to the ground. The DPM (Damp Proof Membrane) is laid under the insulation on top of a soft blinding to ensure it is not punctured. Thanks for the reply. . Buy Now. They can therefore be laid under the DPM (the DPM is still necessary to prevent. DPMs on top of the slab, i. The floor originally had a carpet laid on top of the tiles, when I lifted it nothing felt, looked or smelled damp. Your builder or yourself should have laid dpm under the dpc course on top of the hardcore Base laid on soft building sand . We used the Ultra Floor system, Ultra DPM-it,. We could scrape up the tiles and start again. Relative Humidity: The moisture content or relative humidity of the atmosphere plays is a major factor that affects the drying time of the screed. However the tiler should apply a Primer before screeding such as StopGap P141. Pumped anhydrite floor screeds are not much dearer than ready-mix sand/cement, costing around £25/m3 (laid to a 50mm depth). But what I dont understand is what to do to. Kitchen floor, underfloor heating, screed and DPM. My query is regarding the floor insulation, damp proofing and screed. Ask yourself where the gallons and gallons of water in the slab are going to go - apart from potentially lifting the DPM it will come through any defects in the DPM and cause problems. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn,. 1955 house, recently moved in and presuming no DPM under concrete slab. 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. it could easily be up and down by up to 15mm. Effectively a thick plastic sheet, a damp proof membrane (DPM) is used to create a barrier between a concrete (or screed) subfloor and a wood floor. We have our own in-house delivery fleet of FORS Gold vehicles with Moffett mechanical off-loads delivering nationwide. How to install vacuum insulation panels below a floor screed. Don't use a bitumen at all, you are correct eventually your screed will fail. The current pipes to it will be diverted to another drain to the left of the photo. With the number of planning applications for basement extensions rising by 183% according to research by Halifax, tilers need to be aware. 3k. This reduces the risk of harmful interstitial condensation by ensuring that any moisture within the. . They can therefore be laid under the DPM (the DPM is still necessary to prevent. For technical support please call. No this is designed to be used under floor screeds, tiles, render or plaster. You will need to tear the lot up. . Spacey Super Moderator Staff Member. 75mm pir but we have decided on 100. Fig. 12) Tiles glued. If you are installing where existing floors have been removed, check that there are no traces of previous adhesive residue. 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. When sand-blinded, BAL DPM allows tiling onto difficult substrates such as steel. Water under tiles. heating installations with cementious screeds provided a temperature of 27°C is not exceeded. Sealing a patch of DPM around its edge to the old is easy, just use silicone goo. All modern buildings have what is known as a Damp Proof Course. It’s only to stop the screed running under the insulation. If you noticed the buildup wording is different to the detail drawing, it clearly shows dpm on top of concrete. I'm thinking dpm under the floor board and then 3:1 motar under the DPM to bed on the blocks. Insulation is laid on the concrete and covered with a screed. It is black/blue in colour and comes in conveniently multi-folded rolls. Was looking to do liquid DPM sandwich with fball 1200/F77/1200 (or NA/1cDPM/NA but that’s costing another 30% more. This is resorted to only under the duress of severe time constraint. For traditional screed, the usual total will fall within the range £18. Material. However I'm pretty sure there is no damp proof membrane (or course?) as our water source, a large well, is under the floor and a couple of years ago it flooded into the dining room. Used the primer neat as guidelines suggested. 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. Give it a good wipe with a damp cloth and let it dry before you start. 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 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. 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. 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. DPMs on top of the slab, i. A full sheet DPM is 250 microns (1000 gauge) thickness or above. 25W/m 2 K to meet with building regulations, even if you didn’t plan to. As a waterproofer, BAL DPM is an easy two-coat system when used with BAL Self-Adhesives Butyl Tape in corners and junctions. Our expert team are ready to offer you the very best solution for waterproofing. You'll also need to take the dpm up the walls as well. Price: £4. The concrete slab was usually 100 to 125mm thick. Because we were laying Karndean Flooring to a new extension we needed to check the % RH(relative humidity) of the concrete with a hygrometer. 16 Nov 2016. 100m² per roll. DAMP PROOF MEMBRANE. New-build install: £50 to £75 per square metre. ) • Floating (used to enable installation of thermal or impact sound insulation). As with the Kooltherm installation, start by ensuring a clean and level surface. Try it free. 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. 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. To avoid such issues, it is therefore extremely important to make sure that the screeds are given sufficient time for drying. 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. Outside ground should be. This allows for the full 5kg or just half to be mixed at once depending on the area to be covered. The installation of a liquid damp proof membrane is a vital stage in the construction process, for both new builds and refurbishment work where a structural DPM may be missing or damaged, or where residual construction moisture is present in the floor. When sand-blinded, BAL DPM allows tiling onto difficult substrates such as steel. -markie-, Feb 10, 2020. My DPM was these tiles that were bitumnned/black jacked to the floor. Complete product range for installation, renovation and maintenance of wood flooring. Hull. UFH inside plastic polypanels 75mm screed (probably not liquid). 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. Staffordshire. 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. If Under floor heating is used It is essential that the pipes are laid on. There is a concrete slab in place with a DPM underneath. For bonded screeds, M-Bond Extra epoxy resin combinedWhen laying self-levelling screed, the thickness varies from product to product, however as a general guideline please find the depths below: Minimum depths are usually 2-3mm, however there are some products that can go down to “featheredge”. We have a few options: 1. BBA certified - third party accreditation. 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. or email. 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. Visqueen EcoMembrane DPM. 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. 1200g DPM will be fine.