A revolutionary roof sealing system – ponding water resistant


Catalog Number: 313

Multigum is a professional combined polymers based sealing and coating material, that when dried becomes a very resistant, long lasting sealing membrane. The high flexibility, combined with its resistance to tear, endow the material with a high bridging capability over structural cracks. Multigum is a paste material, easy to use for spray, roller or brush spreading. Multigum is a water-based, user friendly and non-inflammable material.


Multigum is used for sealing new concrete roofs, old bitumen sheets coated with aggregates, old acrylic coatings, old polyurethane coatings and metal roofs.

Multigum is also used for coating and sealing external walls (Multigum matt version).

Technical Specifications


Blue / White paste material

Specific gravity:

1.35 gr/ml


50,000 cps.



Cold Flexibility:


Accelerated weathering in U.V. (2000 hours):

Very good resistance.

Crack bridging capability according to I.S.I. standard no. 4518:

500 cycles of 1mm amplitude plus 6,000 cycles of 3mm amplitude.

Thickness of MULTIGUM – 2mm. (Dry)

No cracks.

Instructions for Use

Surface preparation:

Check that gutters are in good working order, that walls and floor meeting corners are rounded, and verify minimum slopes of 1.5%.

For a new concrete roof:

Application should be performed on a stable, clean and dry structure that was casted minimum 30 days before application.

Remove intensively all loose particles. Apply 300 gr/m² of Primer MS. In case of very porous concrete, apply additional layer of Primer MS, 200 gr/m², after initial drying of the first layer.

Drying time: 1-2 hours. In case of a porous concrete, apply additional layer of Multigum Primer MS in quantity of 150-200  gr/m² . 

Another option: application of Aquapoxy, according to its instructions.

For a roof coated with old acrylic sealing product:

Remove intensively loose membrane parts. Rinse intensively the roof to remove the mud and wait until completely dry. Fill depressions deeper than 8mm with cement mortar, modified with acrylic polymer. Apply 150-200 gr/m² of Primer MS. Drying time: 1-2 hours.

For a roof coated with bitumen membranes covered by aggregate:

Remove loose aggregate particles off the roof. Rinse intensively the roof to remove the mud and wait until completely dry. Apply Primer MS at a quantity of 300 gr/m².

Allow to dry for 1-2 hours.

For a metal roof (galvanized or paint coated):

Remove intensively all sediments and loose particles. Apply polyurethane mastic type Vulkem 921 at all overlap lines between two adjacent metal plates, over the joint between them and over all the screws. Apply Multigum Primer MS - 1 at a quantity of 200 gr/sqm over the surface. Wait 1-2 hours for drying prior to application of Multigum.

In case of paint coated metal roof, it is highly recommended to apply first the waterproofing system on a small spot in order to verify the proper adhesion to the specific paint.

For an old asbestos roofs:

Remove intensively all sediment and loose particles. Rinse intensively the roof to remove the mud and duckweed and wait until completely dry. Apply polyurethane mastic type Vulkem 921 at open overlap lines between two adjacent plates and over all the screws. Then, apply Primer MS in a quantity of 300 gr/ m². Allow to dry for 1-2 hours.

Walls and floor meeting corners, cracks and seams between old sheets:

Ensure that the area is clean of dust. Apply Multigum in quantity of 1.25 kg/m² along the walls and floor meeting corners, gutters, pipe penetration and along cracks (in 20 cm strips).

Performing of sealing layer:

After the Multigum “strips” over the corners and cracks are dry, apply the first layer of Blue Multigum by spraying / brushing over the entire roof area, including the walls in the roof perimeter up to a minimum height of 20 cm or at least 10 cm over the old sealing sheet finishing end, if such exists. Quantity: 1.25 kg/m².

Ensure that the first layer dries for 4-6 hours. A second layer of White Multigum should be applied following the first layer drying.

The overall quantity includes 2.5 kg/m².

In case of application of Multigum on roofs full of devices or in spots which expected to have ponding water , 3 layers of Multigum are needed (1.25 kg/m² for each layer – total quantity : 3.75 kg/m²). drying time prior to application of the third layer-up to 24 hrs.

Apply Multigum also over the parapets in quantity of 1.6 kg/m² - 0.8 kg/m² for each layer.

When using a brush for coating, the layers should be performed in cross brushing directions.

Drying Time

Contact dry time: 4-6 hours (in 25 ºC and 50% R.H).

Final drying: 14 days.


In the shadow, protected from extreme cold (over 5ºC) and high temperature conditions.



Warning and safety measures:

  • Do not swallow, wash hands with water and soap immediately after use.
  • Drying time may change due to variation in temperature and relative humidity conditions, as well as layer thickness.
  • Do not apply 3 days before rain or about 6 hours before dew.
  • Do not apply in temperature below 5ºC, and not more than 35ºC.
  • Multigum should not be diluted, do not add water or any other material.
  • Flood test can be applied at least 14 days after application.
  • Multigum should not be applied in a rate of more than 1.25 kg/m² for each layer. 
  • During the winter time(in temperature under 13 ºC), let the first layer of Multigum dry for 18 – 24 hours prior to application of the second layer. The quantity for each layer will be 800 gr/m².
  • In case the drying time between the first and the second layer of the Multigum is more than 24 hours, you should apply a layer of Primer MS in quantity 150 gr/m² on the first layer and wait 1-2 hours for drying, prior to the application of the second layer.


All materials are not available for all countries. 

Contact your dealer about the availability.

For downloads:

Gallery of product usage