FAQ'S
In order to potentially assist you with any help you require, we have listed our most frequently asked questions below. If you require further assistance, please contact us by clicking here.
Rawmat® HDB Type S1 is supplied 1m wide x 5m long weighing 43kg per roll
Rawmat® HDB Type S2 is supplied 2m wide x 30m long weighing 530kg per roll
Rawmat® HDB Slabseal SS1 is supplied 1m wide x 5m long weighing 43kg per roll
Rawmat® HDB Slabseal SS2 is supplied 2m wide x 30m long weighing 530kg per roll
Rawmat® HDB Type P1 is supplied in 1m wide x 5m long weighing 44kg per roll
Rawmat® HDB Type P2 is supplied 2m wide x 50m long weighing 860kg per roll
Rawmat® HDB Type PP1 is supplied in 1m wide x 5m long weighing 44kg per roll
Rawmat® HDB Type PP2 is supplied 2m wide x 50m long weighing 880kg per roll
Rawmat® HDB Type PJ1 is supplied in 1m wide x 5m long weighing 44kg per roll
Rawmat® HDB Type PJ2 is supplied 2m wide x 50m long weighing 890kg per roll
Rawmat® HDB Type PJW1 is supplied in 1m wide x 5m long weighing 44kg per roll
Rawmat® HDB Type PJW2 is supplied 2m wide x 50m long weighing 890kg per roll
Rawmat® HDB membranes are manufactured to suit the sector in which they are to be used. The list below shows the typical product’s that are used in the different sectors. In certain applications it is possible that products could be used outside of those shown below after approval by our technical team.
Structural Waterproofing
Rawmat® HDB Type S1
Rawmat® HDB Type S2
Rawmat® HDB Slabseal SS1
Rawmat® HDB Slabseal SS2
Rawmat® HDB Type P1
Rawmat® HDB Type P2
Rawmat® HDB Type PJW1
Rawmat® HDB Type PJW2
Petrochemical, Landscaping & Environmental Applications
Rawmat® HDB Type P1
Rawmat® HDB Type P2
Rawmat® HDB Type PP1
Rawmat® HDB Type PP2
Rawmat® HDB Type PJ1
Rawmat® HDB Type PJ2
Rawmat® HDB Type PJW1
Rawmat® HDB Type PJW2
Yes. Rawmat® HDB can be used in saline environments with confidence of the performance due to the prehydration process used during manufacture.
Long term testing has been carried out on Rawmat® HDB and the results have shown no degradation of performance after prolonged submersion in saline conditions.
Yes. Rawmat® HDB can be used as a barrier to the passage of hydrocarbons through the ground. The factory prehydration process protects the clay from breakdown by the hydrocarbons.
Long term testing has been carried out on Rawmat® HDB and the results have shown no degradation of performance after prolonged exposure to hydrocarbon conditions.
Rawmat® HDB can be installed onto contaminated ground and it can even be covered with “as-dug” contaminated material. This can help save expensive costs of shipping “as-dug” material to hazardous waste landfill.
Extrapolation of the long term testing carried out on Rawmat® HDB, predicts the life expectancy of the membrane to be well in excess of 100 years, when installed and maintained in a buried state. The natural sodium bentonite used in Rawmat® HDB is millions of years old and will continue functioning once placed back in the ground. The geotextile carriers used on the membrane, are made from chemically stable polymers and are designed to be resistant to degradation in the long-term.
Rawmat® HDB can be laid in the rain, however, it should not be left exposed and should NEVER be exposed to standing water directly on the membrane. The installation of the Rawmat® HDB membrane should be part of an ongoing process of installation and backfilling with a suitable material. Rawmat® HDB fixed to vertical walls is less vulnerable as the water will run off the membrane.
Yes. Due to the factory prehydration of the bentonite, Rawmat® HDB can be used in calciferous environments. The polymer cocktail used to prehydrate Rawmat® HDB, is taken into the interlayers of the sodium bentonite and protects the sodium ions from cation exchange.
Long term testing has been carried out on Rawmat® HDB and the results have shown no degradation of performance after prolonged submersion in calciferous conditions.
Rawmat® HDB, like any bentonite membrane, requires a confining load on the bentonite to control the swell of the bentonite and to prevent the membrane from drying out. In Structural Waterproofing a blinding concrete layer of 50mm thickness is advised prior to the poring of the slab, this protects the Bentonite from traffic as the re-bar is placed. In other applications where the backfill is soil or stone the depth of cover is dependent on the level of protection it can provide. In normal circumstances 300mm of compacted backfill is required as the confining layer over the Rawmat® HDB membranes.
The central core of the Rawmat® HDB membrane consists of natural sodium bentonite, a high swelling clay, therefore when a nail is fired through the Rawmat® HDB the bentonite will swell and self-seal around the nail which has penetrated through the membrane. If the nail is removed the bentonite will swell and expand to seal the hole created.
Rawell does not have stockists around the UK, we do however, work closely with a number of the leading merchants(contact Rawell if you wish to buy through a merchant). We will supply directly to customers from our manufacturing and distribution facility in Hoylake, Merseyside.
Rawell does not have an installation team for the application of its Rawmat® HDB systems. We can offer training to contractors working with the products for the first time. The system is simple and quick to install, in the past school children have installed Rawmat® HDB as part of their “Nature Study” lessons, this shows how simple installation can be!
Rawmat® HDB can be used to line garden ponds BUT there are a number of things to consider. The Rawmat® HDB needs to be installed on slopes no steeper than 2.5 horizontal to 1 vertical, the Rawmat® HDB needs a minimum of 300mm depth of cover material all over the membrane. Therefore the area required to allow slopes of this angle and sufficient depth of water (at least 1000mm depth) will require a reasonably large area. We don’t usually recommend Rawmat® HDB for ponds smaller than 6m diameter.