Newton CDM 508 Membrane - 8mm Studded Waterproof Membrane

Newton CDM 508 Membrane - 8mm Studded Waterproof Membrane

John Newton & Co. Ltd | Basement Waterproof Membranes

Newton CDM 508 Membrane is a High Quality 'lightweight' (500gsm), BBA Approved, 8mm Studded, Cavity Drain Basement Waterproof Membrane.

Part of Newton System 500, Newton CDM 508 is suitable for the waterproofing of earth retained walls and vaulted soffits and is guaranteed against deterioration for 30 years.

  Newton CDM 508 is supported by BBA Certification Certificate Number 94/3010.

Supplied in (W) 2.47M x (L) 20M (48M²) Rolls.


Newton CDM 508 Membrane

Newton CDM 508 is a high quality 'lightweight' Cavity Drain Waterproofing Membrane for use within Newton System 500, Newton's internally applied Waterproofing System that includes Newton Drainage and Pumping Systems.

Newton CDM 508 is suitable for the waterproofing of earth retained walls and vaulted soffits and is guaranteed against deterioration for 30 years, with a life expectancy of the design life of the building (DIN 9001:2000).

Newton CDM 508 is inert and, therefore, non-polluting to drinking water, highly resistant to water, alkalines, saline solutions and organic acids, and not affected by minerals and hydrocarbons. It is also rot-proof, and resistant to bacteria, fungi and other small organisms.

Benefits & Features:

  • Does not require extensive and damaging preparation to the wall surface

  • Speed of installation

  • Provides vapour control when used with humidity control systems and is capable of delivering an environment to all levels within a Grade 3 environment to BS 8102:2009

  • Resistant to rot, chemically aggressive groundwater, acids and alkalines, efflorescent salts and hydrocarbon contamination

Technical Data:

Membrane Material HDPE
Membrane Thickness 0.8mm
Stud Depth 8.0mm
Density 500g/m²
Vicat Softening Temperature 126°C
Service Temperature -40°C to +80°C
Compressive Strength (EN 25619-2) 170 kpa
Thermal Conductivity (EN12667) 0.461 W/mK
Water Vapour Resistance - Sd Value (BS EN 1931) >604m
Water Vapour Resistance - μ Value >1208000μ
Water Vapour Diffusion Resistance >3020 MNs/g
Resistance to Fire (BS EN 13501-1) EuroClass
Chemical Resistance - Excellent (EN 14030) 100%
Oxidation Resistance - Excellent (EN ISO 13438) 100%
Radon Gas Resistance - Membrane* (K124/02/95) N/A
Radon Gas Resistance - Joints* (K124/02/95) N/A
Resistance to Liquid Hydrocarbons* (EN 16140:2011) N/A
Carbon Dioxide Permeability* N/A
Methane Permeability* N/A
Carbon Dioxide Transmission Rate (ISO 15105-1) N/A
Methane Transmission Rate (ISO 15105-1) N/A
The above data, even if carried out according to regulated tests are indicative and they may change when specific site conditions vary.¹After 14 days immersion in petrol and engine oil. *At the time of testing, the membrane was called Newton CDM 508. Product name changed to CDM 508R to reflect the gas and liquid hydrocarbon capabilities. The currently named Newton 508 has not been tested for resistance to gas or liquid hydrocarbons. **The test was carried out in accordance with Vinci In-House Test Procedure TP950/05/13569, issue 1, and Rilem Report 12, Performance Criteria for Concrete Duribility, E & FN Spon, London, UK, pp 226-230. All test certificates are available by request.




Newton CDM 508 can be installed over a wide range of substrates in varying situations - walls, ceilings, soffits, etc. However, before the system is installed, the area must be assessed to determine what preparation is required:

All timber and other organic material must be removed to prevent risk of fungal or bacterial growth behind the System, e.g. skirting boards, timber plates, old wallpaper etc. If evidence of rot exists, this must be dealt with by a specialist contractor prior to installation of the system (See our Woodworm & Dry Rot Control Products). If any mould, etc. exists, this should be cleaned off and the area sterilised with a Fungicidal Wash.

If the walls are uneven or areas have deteriorated, any large depressions should be levelled and made good to ensure a solid fixing

When fixing the system to flat soffits you must ensure that there is a fall to create proper drainage and prevent ponding. Any sagging of the membrane should not be great enough for ponding to take place

New concrete should be treated with Platinum Lime Inhibitor which prevents free lime from the curing concrete being drawn out by ingressing water.

Wall Application

Application on Walls:

Newton 508 is fixed with the studs against the wall to create an air / depressurisation gap.

The membrane can be fixed either vertically or horizontally. When making this decision, you will need to take into account the size of the area to be lined, and the height of the walls relative to the width of the membrane. 

Horizontal fixing requires less cuts and jointing but the full roll is very heavy at first. Vertical fixing has much lighter strips to fix, but requires that each of these is taped back together again. You may find that vertical fixing is easier, but requires more Newton CDM Waterseal Tape for jointing.

The membrane is fixed to the wall with the Newton CDM MultiPlug. The MultiPlug has a soft rubber sealing washer fitted to the plug for sealing to the wall membrane.

Place the membrane in position as level as you can judge by eye. Using a 10mm Drill Bit, drill through the centre of a stud near the top and edge to a depth greater than the fixing.

The fixing is then hammered into the pre-drilled hole until the plug sits flush in the stud. The rubber washer re-seals the hole. Level the membrane using the spirit level or laser level if used, and fix another plug about 2 metres along at the top of the sheet. The membrane will now be hanging level to the wall.

If you are fixing horizontally, continue fixing every 2 metres until you have reached the end of the roll or you have covered all of the wall(s) to be treated. It is very important to regularly check the level. If the membrane is not level, you may well find that the membrane is kinked and looks unsightly, it will also dive down when fitted around corners.

If you are fixing vertically, hang each subsequent sheet by the two fixings as described above. The subsequent sheet should overlap by at least the width of the flange of the new sheet. You may find it easier to interlock the first stud of the new sheet to the last stud of the last sheet as this helps to keep the new sheet level.

The vertical joints have to be sealed with Newton CDM Waterseal Tape. It is easier to apply the tape to the inner surface of the flange of the next sheet. Clean the flange and the face of the last sheet with a clean rag.

When you have fixed the new sheet level with the correct overlap, pull off the backing paper from the tape and peel down whilst applying pressure to the flange.

Once all the backing paper has been removed, apply more pressure with the palm of your hand to further seal the whole of the joint. A Hot Air Gun should be used to help sealing, especially in cold or damp conditions.

Fixing Centres:

Once the wall membrane is hanging from the top fixings the rest of the fixing plugs need to be fixed.

The spacing of these fixings is dependant on the type of wall finish to be used:

  • Timber Battens - 600mm centres vertically and 400mm horizontally.

  • Barrel Vaults - Tighter centres 300mm around the vault and 600mm down the vault.

  • Fixed Metal Track (Gypliner) - 800mm centres vertically and 600mm horizontally.

  • Brick or Block Walls restrained to the retaining wall using ties should have the fixings at centres to provide the correct number of restraints at the correct centres.

  • Free standing timber and metal frames and free standing block walls do not require specific fixing centres. In these cases use sufficient fixings to ensure the membrane is neat and tidy and reasonably tight to the wall, especially around corners and reveals.

  • When fixing the system to vaulted soffits you must ensure that enough fixings are used to keep the wall membrane tight to the soffits with no sagging.

  • All fixings should be in line both horizontally and vertically.


Battens should be pre-treated and of a minimum dimension of 25mm x 38mm although you may find that 25mm x 50mm offers better fixing at the edge of the plasterboard.

The battens can be fixed into the Newton CDM MultiPlug without piercing the membrane, by using 5mm (size 10) self-tapping screws. The plug will take 30mm of screw, so be sure to purchase the correct length for the thickness of batten.

Over-tightening of over length screws can loosen the plug. Be very careful not to puncture the wall membrane when drilling and fixing the battens. Battens should be fixed so that all plasterboard edges are supported. Use a Timber Treatment to protect cut battens.

Once the battens are fitted into position, plasterboard can be fixed to them using clout nails or preferably plasterboard screws. Care should be taken not to exceed the depth of the battens with the screws, and thereby puncture the membrane.

Alternative Fixings:

Other finishes may be employed depending on the requirements of the specifier.

Free Standing Frame:

This method should be employed if the wall is undulating, as with some stone structures or where space loss is a secondary consideration. The frame would be fixed to the soffit and the floor finish with the supplied ‘U’ channels.

With the increasing requirement of insulation to meet Part ‘L’ of building code, the use of these frames is becoming more popular, the thickness of insulation required is often in excess of the thickness of the frame, and so the use of these frames does not add extra depth to the wall build when using this method.

Because the frame is free standing and has no relationship with the wall membrane, very few fixings are required and so this wall finish above allows for the fastest and most efficient method of fixing Newton CDM 508 to the wall.

Proprietary Fixing Systems:

Fixing systems such as Gypliner or Lafarge can be used with Newton System 500. It is also possible to use metal profile systems when constructing new internal walls.

Internal Block Walls:

If preferred the system can provide a water and vapour proof barrier, and then be lined with a block or brick inner skin. Special ties are available that fit into the Newton CDM MultiPlug for lateral restraint of the internal wall. The ties and retaining clips can also be used for the fixing and holding in place the wall insulation.


Installation to Vaults:

A ceiling which is to be covered, as in a vaulted cellar construction, should be fixed and lapped in such a way so that water does not pond behind the system.

The laps and joints should also be detailed correctly to allow correct drainage, and prevent water from sitting on joints. Newton CDM Nuseal Plugs with a seal made from Newton CDM Waterseal Rope should be used for application to vaulted ceilings.

Where flat soffits are being considered it is imperative that they should have a fall in line with drainage requirements.

Again, sagging of the membrane should be avoided to prevent ponding.


Where Newton System 500 is to be installed in vaulted cellars our experience shows that the best method of application is as follows:

Measure the depth of the vault from front to back wall and allow for a down turn at each end of 200mm. Unroll the sheet and cut to size.

Estimate the approximate centre of the arched ceiling and mark it. Measure down the arch 1.2 meters from there and again mark it. Strike a horizontal line along the wall from back to front. This will give you a guide line for your sheet edge as you fix it along the length of the ceiling, thereby keeping your sheet sections symmetrical. You may wish to hammer in masonry nails to the guide line to give a physical edge to the guide line.

Offer up your first section of membrane to the ceiling allowing a lap to the back wall of 200mm. Using your guide line to keep the sheet square, drill and fix the sheet along the apex of the arch following the same line of studs.

The Newton CDM Nuseal Plug with Newton CDM Waterseal Rope should be used to seal the plugs.

NOTE: The Newton CDM MultiPlug should not be used for this application as the rubber washer sold with the MultiPlug is not suitable.

The fixings should be fixed through the centre of the membrane studs at approximately 600mm centres.

It should be remembered that the plugs provide the fixing points for your battens; therefore they should be kept in line.

Your next section of membrane is again cut to size allowing a 200mm lap at each end. Before offering up the next sheet, a Newton CDM Waterseal Tape joint should be applied to the edges of the first sheet, either on the flanged edge or between the last two rows of studs on the none-flanged edge.

With the protective paper left on the tape you can now offer up the next sheet ensuring that you use the flanged edge to overlap onto the sealing tape.

Once you have the second sheet positioned correctly over the sealing tape, remove the protective paper working out from the middle and effect a seal.

You can now carry on fixing the sheet as previously described. This process is repeated until you have covered the arched walls to the springer and the vertical walls below the springer, maintaining a 200mm lap to the end walls.

Vaults - End Walls:

At the end walls of the vaulted construction an ‘end piece’ of flat membrane is fitted to the end wall of the vault. The 200mm lap from the soffit membrane is cut in fans to fit the curve and sit neatly against the wall, filling each cut with a small piece of Newton CDM Waterseal Rope or Newton CDM Waterseal Tape. Do not make the cuts all the way up to the ceiling and make as few cuts as possible.

Measuring the highest point of the arch, the ‘end piece’ membrane is cut to size and fixed to the end walls in front of the fanned ceiling membrane. The membrane is then trimmed to fit neatly into the curve of the ceiling.

The end wall membrane is then pulled back at the sides and around the arch to expose the studs on the reverse side.

Using Newton CDM Waterseal Rope, a joint is made by the same method at the stud / stud joint details, with the exception that around the arch the rope should follow the contour of the ceiling curve.

Door Reveals:

When you fit the Newton Membrane to the end wall with the door opening, please bear in mind that you will have to fit a section of membrane around the door head and lapped down the sides by approximately 100mm.

You can then wrap the wall membrane around the sides, maintaining the correct drainage detail and forming an overlap.

This application detail will produce a small gap on the angle of the door opening.

This should be sealed using Newton CDM Overtape. Alternatively, Newton DampSafe 601 Slimline Membrane can be used a flat DPC in lieu of the studded membrane if space is limited.

Overhead Intrusions:

Where service pipes, electrical wiring or other intrusions occur overhead or around the arch, these should be re-sited to a vertical surface where they can be better sealed and re-situated on the dry side of the system.

Most services can be concealed between the battens. Services and protrusion should be collated where possible and passed through a pipe sealed with one of the Newton pipe sleeve options.

Data Sheets

Technical Data Sheet

Newton CDM Installation Manual

Declaration of Performance (DoP)

BBA Certificate

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