7/27/2015 DERBIGUM | Specs | Balconies

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Balconies, Terraces and PatiosGeneral

This section typifies pedestrian­trafficable areas such as balconies, patios and terraces under fullybonded tiles or pavers. These areas present some of the most difficult situations from a waterproofingpoint of view because there are often many complex situations in usually confined areas. The cost of thewaterproofing is often but a fraction of the cost of the finishes ­ consider the cost/risk ratio and give highpriority to the design, surface preparation and installation. Derbigum adopts a pragmatic approach andrecommends the use of a dual­layer waterproofing system to reduce the risk of labour error and thepossibility of subsequent damage.

Substrate

As with most membranes and coatings, the substrate plays an integral part in the success of the system.Too often Waterproofing Contractors do or are compelled to install the waterproofing system oninadequate or poorly prepared surfaces. Surface preparation is essential to the success of thewaterproofing system.

The substrate shall be surface dry, clean and smooth; free of voids, protrusions and contaminants. Thearea is then to be primed using a bituminous primer. Internal corners shall be coved and external cornersrounded.A screed to falls is to be laid on the concrete surface to receive the waterproofing membrane.

Specification

Specification

One layer Derbigum CG4 on one layer Derbigum CG3 laid staggered, with sidelaps of 75 mm and end laps of 100 mm, fully sealed to primed screeded surfaceby "torch­fusion", followed by one layer Derbigum Interdek with 50 mm laps, laidloose on waterproofing as isolation/protection layer, to receive fully bondedtiles/paving on a mortar bed of minimum 45 mm (elsewhere specified).Waterproofing to be installed by an Approved Derbigum Contractor.

Isolation Layer

Tiles or Pavers bedded in mortar are to be laid on an isolating membrane, such as Interdek or a pvcsheeting, so as to reduce stresses placed on the waterproofing by possible movement in the paved finish.This further facilitates access for remedial work if required. Movement joints (soft joints) between thetiles/pavers are to be created at approximately 3 metre centers and at all abutments.

It is recommended that the minimum thickness of the mortar bed is 45mm.

Outlets

The waterproofing is to be fully dressed into the drainage outlets to ensure a watertight seal.A fully bonded soaker flange is recommended. Outlets are to be positioned so that they are easilyaccessible both for the Waterproofing Contractor at the time of installation and maintenance purposes atsome future date. Ensure that the level of the flange is kept below the screed level so as to preventponding around the outlet.

Balconies, Terraces and Patios Spec

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General

Substrate

Specification

Isolation Layer

Outlets

Flood Test

Abutment andEdges

Thresholds

7/27/2015 DERBIGUM | Specs | Balconies

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Flood Test

The integrity of the waterproofing system should be established by means of a flood­test of 48hrs – 72hrsduration, prior to handing over to the contractor. A certificate is to be obtained from the professional teamrecording the date and time­period of the test and that the waterproofing system was handed over in aclean, proper and watertight condition.

Abutments and Edges

The height of the waterproofing membrane turnup is to be a minimum of 100mm and always above theheight of the final tile or paving finish. Detailing of abutments requires careful attention to achieve apermanent, watertight and aesthetic finish. A soft joint must be created at all abutments to prevent damage to the waterproofing system caused bymovement.

Thresholds

The height of the door threshold is of paramount importance. The minimum height of the waterproofingturnup should be 100mm. The finished height of the waterproofing (turnup) is to be higher than thefinished paving surface. This is to ensure that surface water does not penetrate behind the skirting. Special precautions are to be taken so that wind­driven rain is prevented from entering the interior.Door and window frame fixing methods require careful detailing and should be done in consultation withthe frame manufacturer. Too often the frame is fixed mechanically through the waterproofing membrane.

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