Polythene And Polyethylene Sheet
Polythene or polyethylene sheet is often used as a damp-proof membrane with oversite concrete for all however severe circumstances of dampness. It is suggested that the sheet should be at the very least 0.25 mm thick (1200 gauge). The sheet is provided in rolls four m huge by 25 m long. When used below concrete oversite the sheet needs to be laid on a blinding layer of sand or compacted fuel ash spread over the hardcore.
The sheets are spread over the blinding and lapped 150 mm at joints and continued throughout surrounding walls, below the dpc for the thickness of the wall.
Where site circumstances are reasonably dry and clean, the overlap joints between the sheets are sealed with mastic or mastic tape between the overlapping sheets and the joint completed with a
polythene jointing tape as illustrated in Fig. 29.
For this lapped joint to achieve success the sheets must be dry and clear else the jointing tape will not adright here to the surface of the sheets and the joint will rely upon the load of the concrete or screed pressing the joint sufficiently heavily to make a watertight joint. As clear and dry situations on a building site are uncommon, this type of joint needs to be solely used where there may be unlikely to be heavy absorption of ground moisture.
The place site conditions are too moist to use mastic and tape, the joint is made by welting the overlapping sheets with a double welted fold as illustrated in Fig. 30, and this fold is stored in place by weighing it down with bricks or securing it with tape till the screed or concrete has been placed. The double welt is formed by folding the sides of sheets collectively after which making a welt which is flattened.
The plastic sheet is successfully not possible to fold and so stiff and elastic that it's going to all the time are likely to unfold so that it requires a deal of persistence to fold, hold in place after which contrive to fold alongside the joint. Through the use of the maximum measurement of sheet available it's attainable to minimise the number of joints.
The sheet must be used in order that there are only joints a technique as it is impractical to kind a welt at junctions of joints.
The place the extent of the damp-proof membrane is under that of the dpc in walls it is mandatory to show it up towards walls in order that it could possibly overlap the dpc or be. turned over as dpc as illustrated in Fig. 31. To maintain the sheet in place as an upstand to partitions it is necessary to maintain it in place with bricks or blocks laid on the sheet towards partitions until the concrete has been placed and visqueen dpm the bricks or blocks removed as the concrete is run up the wall.
On the internal angle of walls a minimize is made in the upstand sheet to facilitate making an overlap of sheet at corners. These sheets which are commonly used as a damp-proof membrane will serve as an efficient barrier to rising damp, providing they aren't punctured or displaced throughout subsequent building operations.
The sheets are spread over the blinding and lapped 150 mm at joints and continued throughout surrounding walls, below the dpc for the thickness of the wall.
Where site circumstances are reasonably dry and clean, the overlap joints between the sheets are sealed with mastic or mastic tape between the overlapping sheets and the joint completed with a
polythene jointing tape as illustrated in Fig. 29.
For this lapped joint to achieve success the sheets must be dry and clear else the jointing tape will not adright here to the surface of the sheets and the joint will rely upon the load of the concrete or screed pressing the joint sufficiently heavily to make a watertight joint. As clear and dry situations on a building site are uncommon, this type of joint needs to be solely used where there may be unlikely to be heavy absorption of ground moisture.
The place site conditions are too moist to use mastic and tape, the joint is made by welting the overlapping sheets with a double welted fold as illustrated in Fig. 30, and this fold is stored in place by weighing it down with bricks or securing it with tape till the screed or concrete has been placed. The double welt is formed by folding the sides of sheets collectively after which making a welt which is flattened.
The plastic sheet is successfully not possible to fold and so stiff and elastic that it's going to all the time are likely to unfold so that it requires a deal of persistence to fold, hold in place after which contrive to fold alongside the joint. Through the use of the maximum measurement of sheet available it's attainable to minimise the number of joints.
The sheet must be used in order that there are only joints a technique as it is impractical to kind a welt at junctions of joints.
The place the extent of the damp-proof membrane is under that of the dpc in walls it is mandatory to show it up towards walls in order that it could possibly overlap the dpc or be. turned over as dpc as illustrated in Fig. 31. To maintain the sheet in place as an upstand to partitions it is necessary to maintain it in place with bricks or blocks laid on the sheet towards partitions until the concrete has been placed and visqueen dpm the bricks or blocks removed as the concrete is run up the wall.
On the internal angle of walls a minimize is made in the upstand sheet to facilitate making an overlap of sheet at corners. These sheets which are commonly used as a damp-proof membrane will serve as an efficient barrier to rising damp, providing they aren't punctured or displaced throughout subsequent building operations.