ISOTHANE EM



	APPLICATION NOTES Description This bulletin is intended to be complementary to the Isothane EM Product information by providing additional information and explanation, hints and advice about their application. It will be updated periodically in the lights of developing practices and techniques. The concept of a liquid applied elastomeric membrane as a waterproofer is a simple but effective one, especially when formulated on moisture curing urethanes because the chemistry of the system enables it to cross-link by reaction with atmospheric moisture. Liquid application allows a seamless membrane to be applied to a whole area, following surface contours and undulations intimately. The elastomeric nature of the membrane enables it to accommodate a degree of movement in the substrate, although it is essential that the structure supporting the substrate is sound and stable. If the substrate does not adhere to the underlying structure or contains silicone or stearates from pervious treatment adhesion will be suspect and failure may occur. Due consideration should be given to any vapour drive and its preferential direction dependent on the use and circumstances of the building. Roof structures, especially flat ones, should not be expected or designed to be permeable to water vapour as a means of ventilating the structure. Positive ventilation in the form of wall vents, roof vents or opening windows is the best method of removing large amounts of water vapour from a building. Isothane EMA and EMC are vapour permeable, EMB is, for practical purposes a vapour barrier. Areas of Application Roofing Isothane EM can be used on most types of roof and roof substrate provided that proper preparation is carried out. This includes roofing felt, asphalt, bitumen, slates, tiles, asbestos, concrete, brick, wood, glass, ferrous metals, lead and copper. Porous substrates must be sealed with Isothane P, as should bituminous substrates before application of Isothane EMB. Balconies and Decks Isothane EM can be used for balconies and decks not subject to heavy foot traffic. In such cases at least 1.5 mm coating thickness should be applied and a reinforcing scrim embedded into the first coat is recommended. In order to improve foothold, fine dry aggregate or silica sand should be broadcast over the last application before it fully cures. Tank and Pipe Coating Isothane EM can be used as protective or solar-effective coating on tanks and pipe installation. For sub-ground or buried installations Isothane EM/B should be used because of its good corrosion protection. Sprayed P.U. Foam Isothane EM has excellent adhesion to sprayed p.u. foam and can be used as the weatherproof coating on this type of foam insulation without the need to use a primer. The foam suppliers recommendation should be followed with regard to overcoat times. Sub-Ground Structures Isothane EM can be used to waterproof subground concrete structures. Isothane P should be used to prime surfaces and the instructions for cementitious and porous surfaces followed. If the structure will be subject to backfiring a sufficiently thick membrane must be applied to guard against penetration of the membrane by sharp aggregate. Ponds and Water Systems Isothane EM should not be used to line garden ponds, swimming pools and domestic and potable water systems. Application Note A liquid applied membrane is not a paint and requires a higher applied thickness than a paint in order to provide protection and enable its elastomeric properties to be achieved. The minimum membrane thickness must be 1 mm and this can be achieved with due consideration for the following: Two applications of 0.5 mm each will tend to eliminate thin areas and pin holing but will incur greater labour costs. Care must also be exercised to ensure the second application takes place within the specified overcoat time to ensure good adhesion. If the recoat time is exceeded Isothane P must be used to ensure good intercoat adhesion. A single application of 1 mm thick membrane reduces labour costs and eliminates problems of reapplication within the specified time limit. Care must be exercised to ensure a uniform application of the membrane avoiding thin areas and pin holing. Surfaces subjected to light foot traffic should have a 1.5 mm coating and it is advisable to use scrim reinforcement in the first application. More heavily trafficked areas may have rounded aggregate spread over the final application in which case a scrim reinforcement should certainly be used. The bare membrane surface may be slippery when wet and it may be expedient to sprinkle fine dry silica sand onto the surface as it dries in order to impart a non-slip finish. Methods of Application Isothane EM and P can be applied by brush, roller or airless spray. If spray is to be used a Graco King / President 60 to 1 ratio or equivalent is required. * Compressor: 100 psi 60 cfm min * Tip Size: 28/30 thou 60 angle * NOTE: Stir before using with spray equipment

Application Procedures
Cracks and Depressions
Cracks not liable to movement should be filled with mastic filler. Allow for the solvents they contain to evaporate. Deep depressions should be treated similarly. Prime with Isothane P prior to the application of two thick coats of Isothane EM. Where water is likely to pond, three thick coats should be applied. Do not apply in coats of more than 1 mm thick but any number of coats can be applied at 24 hours intervals.

Expansion Joints and Cracks Liable to Movements
Clean surrounding surfaces. Where joint sealant does not fill joint, pour in Isothane EM until flush with surface. Prime joint to a minimum width of 30 cm. Apply a coat of Isothane EM whilst wet, embed 30 cm wide strips of reinforcing fabric scrim material, overlapping where necessary, avoiding creases and bubbles. Immediately overcoat, extending at least 15 cm either side. Do not stretch the fabric. Bolt heads etc., should be given two coats before proceeding with general applications.
Isothane Slip Primer should be used where excessive movement is a problem. Isothane Slip Primer provides an alternative methods of dealing with movement of cracks and joints etc. by dissipating the stresses caused by substrate movement over a wider area and hence allowing the membrane to accommodate the stress without tearing. When the joint or crack has been filled up to the surface level, Slip Primer should be applied along it to a minimum width of 10 cm and allowed to partially dry. Slip Primer will not totally dry and will always stay tacky thereby providing some adhesion but allowing "slippage" under the membrane to accommodate the movement.

Rigid Sheet Roof - ( metal, Asbestos, etc.)
Holes and cracks in sheet roofing cannot be repaired with mastic since the sheet has no significant depth in which to provide a key. Damage should therefore be patched with scrim of sufficiently dense construction to be impregnated with Isothane P. When the total roof area has been cleaned and is dry, the area surrounding the damage should be primed with Isothane P, overlapping the damage by at least 10 cm all round. A piece of scrim, slightly smaller than the primed area, should be impregnated with Isothane P and positioned over the damage while the primer is still tacky. When the patch is nearly tack free the whole roof area should be primed with Special Primer and Isothane EM applied in the prescribed way.

NOTE: Large holes in the roofing sheet will require replacement of the sheet. When a hole is being patched with scrim the overlap must be large enough to prevent the impregnated scrim sagging.

Abutments, Flashing, Valleys, Vents Bases, Up stands, etc.
Isothane EM is self flashing and can be used on up stands. In such cases the angles between the horizontal and vertical surface should be covered
with a 30 cm scrim bandage. This should be embedded into the first Isothane coat immediately after application, thoroughly rolled to prevent creases and bubbles. Continue up vertical surfaces to a minimum distance of 15 cm's. Apply two coats of Isothane EM. Alternatively use a cant strip or
cover fillet where verticals meet horizontals at a right angle.

Special Substrate Preparation
Bituminous Surfaces (e.g. Roofing Felt, Asphalt, etc.)
Remove all loose chippings, dust, fungus etc. Note that where chippings remain embedded, the surface area is substantially increased and will
require a greater volume of both Isothane P and Isothane EM in order to obtain the 1 mm membrane thickness. At least three coats are recommended in such cases. Cut open blisters, paint underside with Isothane EM and secure with felt tacks, brush out extruded liquid. Allow to dry thoroughly, including the evaporation of moisture from within the layers of felt. Apply Isothane P to achieve a uniform coating then apply Isothane EM as directed above within 48 hours.

Cementitious and Porous Surface (Concrete, Cement rendering, asbestos sheeting, etc.)
Allow at least 28 days to provide drying time for new concrete. Clean off all laitance, loose and foreign material. All friable or dusting surfaces
should be cleaned back to a firm base, apply Isothane P as above. On very absorbent surfaces a two-coat application of Isothane P is
recommended. For initial priming coat only, Isothane P may be diluted with up to 20 % High Flash Aromatic Solvent.

Slates and Tiles
Clean thoroughly and carry out necessary structural repairs. Apply Isothane P to cementitious substrates and porous surfaces such as asbestos cement tiles. Note that a continuous membrane over tiles may inhibit ventilation of the
roof void and cause internal condensation, so ensure that adequate ventilation is provided.

Metal
Ferrous: Remove coatings, rust and scale by mechanical means or wire brushing where rust is superficial. Apply Isothane P to clean dry surface
as soon as possible after preparation. Do not use on deeply rusted metals, without first priming with anti-corrosive primer.
Non-Ferrous: Mixed substrates such as rusted galvanized sheeting should be prepared as above. Non-rusting galvanized steel should be degreased
and primed with Isothane P.
Lead, copper, brass, and stainless steel: These should be cleaned, degreased and coated with Isothane P.

Metal Backed Flashing Strip
New metal-backed flashing strips may have residual silicones on their surface. Wash with H.F.
Aromatic solvent. Allow to dry and roughen surface with sandpaper before applying Isothane P and Isothane EM.

Wooden Surfaces
Remove all paint and varnish and apply Isothane EM directly to a clean dry surface. Where wood is unseasoned and likely to be damp or porous, such as plywood and chipboard, apply Isothane P first. Always use Isothane P on timber roofs. Make sure that chipboard or plywood is of exterior quality and ensure that timber has not been subjected to silicone, stearate or other water repellent treatments.

Application Procedure
Follow the procedure laid out in the product information sheet.

Finishes
Chippings
Although Isothane EM does not degrade with UV, high levels of solar heat gain can affect any bituminous coatings, which may be beneath the
Isothane EM. If the surface is not subject to foot traffic, chippings can be applied. In such cases a three-coat application of Isothane EM is
recommended.

Solar Reflective Top Coats
To minimize solar heat gain, solar reflective finishes can be applied to Isothane EM/B. Isothane EMA can be used after applying Isothane EMB but an intermediate coat of Isothane P is recommended to minimize discolouration. Other solar reflective finishes can be applied to fully cured Isothane EM according to manufacturer's' instructions.

NOTICE
This information is of general nature and is supplied without recommendation or guarantee. It does not make claim to be free from patent infringement. Properties shown are typical and do not imply specification tolerances. Liability for loss or damage through use cannot be accepted except for death or injury caused by negligence on the part of Liquid Polymers PLC. Whilst these specifications are based on expert knowledge, practical experience and laboratory testing, successful application depends upon the nature and conditions in which the products are applied. Users must, by comprehensive testing, ensure suitability of product for own use. Without control or supervision of the preparation for and application of Isothane products, general guarantees cannot be offered.

PROTECTIVE COATINGS