Waterproofing Membrane

Pre-fabricated waterproofing membrane made of distilled bitumen and plastomeric polymers (APP) having a woven non woven single strand composite polyester reinforcement, which provide the membrane with good mechanical characteristics and excellent dimensional stability.

The PA versions are self-protected on the upper face with mineral slates which reduce superficial heat absorption improving the durability of the membrane.
The self-protected versions have a side selvedge of 10 cm and upon request a head selvedge of 15 cm, to improve adhesion between the sheets.

  • For the application of the membrane the use of heat is generally used by means of a gas torch or specific hot air machine. Use protective devices required by law. The application by heat is not suggested when on heat sensitive materials (polystyrene insulation).
  • Coordinate the operations in a way to not cause damage to the construction elements and underground structure. Avoid to leave the structure for the night or for periods of prolonged work interruptions without having been properly sealed.
  • The application surface must not have any depressions to avoid the risk of ponding water, the slope must be at least 1.5% on concrete decks and 3% for steel or wooden ones, this to guarantee a proper run off of rainwater.
  • The water drainage spouts should be sufficiently big enough to allow for rain water to be eliminated in an efficient way.
  • Prepare cementitious substrates, including verticals and details, with a bituminous primer either by brush or airless, approx. 300/400 gr/m2.
  • Allow this preparation layer to dry before proceeding with any other operation.
  • With prefabricated constructions, apply a suitable reinforcing strip along all joints. In the presence of construction joints, prefabricated panels or metal decks, suitable expansion joints are to be considered.
  • All details, perimeters, verticals, change of slope as well as projecting area must be apply fully bonded.

• On cementitious surfaces and similar apply, by roller or airless, bituminous primer, approx. consumption 300 gr/m2.
• Apply by torch application a 25 cm strip of membrane reinforced with polyester along all vertical up stands.
• To have all overlaps with the slope, position the membrane always starting from the lowest point. (Draw. N.1)
• Position the membrane sheets staggered, avoiding to create any overlaps against the slope and the drains. (Draw. N.2)
• Cut the corners of membrane sheet which will be laid under the next sheet at a 45° angle (10 x 10 cm). (Draw. N.3)
• The joints, both side and head, must be respectively overlapped by 10 & 15 cm. (Draw. N.3)
• The second layer of membrane will be applied astride and over the first one, always in the same direction, and approx. 1/4 of its length from the previous sheet. (Draw. N.4)
• The bituminous membrane will be applied with a propane gas torch to the substrate. It is necessary to heat the entire surface, except for the side & head laps, making sure that the compound forms a liquid mass in front of the roll to assure that it saturates any superficial porosity.
• The side laps (10 cm) and head laps (15 cm) will be heat welded with an appropriate torch; during this stage the overlaps should be pressed by using a roller (15 kg) from which a bead of compound should flow and therefore avoiding to have to iron the overlaps.
• Apply the vertical membrane sheet having the same characteristics of the waterproofing membrane and dimensions equal to the width of the roll, making sure that it overlaps the horizontal one by at least 10 cm, heating it with a gas torch and squeezing it with a trowel until a bead of compound appears from underneath.
• The height of the verticals must be equivalent or superior to the finished surface by at least 15 cm.

To best use the technical characteristics of bituminous membranes and guarantee the maximum performance and durability of the jobs where they are used, some simple but fundamental rules must be respected.

  • The rolls are to be stored in an upright position, indoors in a dry and ventilated area, away from heat sources. Absolutely avoid the stacking of rolls and pallets for storage or transport to avoid possible deformations which may compromise a perfect installation. It is recommended to store the product at temperatures above 0°C.
  • The rolls shall be kept in a warm or heated storage area during application, should the workability of the material deteriorate or become stiff and difficult to install during application, these should be returned to the heated storage area and substituted with new rolls. The rolls that are temporarily stored on the roof before application, shall be kept elevated by being left on their own pallets and shall be covered and protected from the weather.
  • The application surface must be smooth dry & clean.
  • The application surface must be previously treated with a suitable bituminous primer, to eliminate dust and enhance the adhesion of the membrane.
  • The application surface must not have any depressions to avoid the risk of ponding water, the slope must be at least 1.5% on concrete decks and 3% for steel or wooden ones, this to guarantee a proper run off of rainwater.
  • In situations of application on vertical surfaces superior to 2 meters or on very sloped substrates, apply suitable mechanical fixings to the head laps, after which they will be sealed when torching the head laps.
  • The application must be done at temperature higher than + 5°C.
  • The application must be interrupted in adverse weather conditions (high humidity, rain, etc.).
  • The materials without mineral self-protection or P+V, used as a top layer (cap sheet), can be painted with an aluminium coating to improve and extend the performance and life expectancy, the material should be allowed to oxidize approx. 3-6 months before being coated. An alternative, depending on the type of construction, it is possible to use heavy protection (floating pavements, stone, etc.).
  • The pallets on which the rolls are packaged are intended for normal warehouse use.
  • The materials on stock should be rotated following a first in first out rotation.