SHEET WATERPROOFING. Waterproofing and drainage 1 Sheet waterproofing [1]

Transcription

1 SHEET WATERPROOFING When faced with unstable substrates, crack risk, and possible high vapour pressures from inside (also in flooring subject to significant live or dead loads), one cannot use liquid waterproofing. The alternative consists of non-base-bonded waterproofing systems, in this documentation termed sheet waterproofing (though such systems could also be called waterproof blankets or films). Though base-bonded waterproofing can also be applied on to certain types of substrates, under particular conditions, such as various bituminous products [which may be liquid and be brushed on, reinforced with mineral fillers, modified with synthetic materials, contain different components, mastics, etc.], since these systems are not customarily used under modular rigid coverings, they have not been included in this documentation. With sheet waterproofing, it is also common to find a decoupling layer beneath the waterproofing and, in particular, to have a protecting layer on top, always comprising a separating layer and a screed with a minimum thickness, depending on the expected stresses, in the case of flooring. German standard DIN on waterproofing in building works, in its different parts, constitutes a full, precise documentary reference. Part 5 (waterproofing against water without pressure), Part 8 (waterproofing on movement joints), and Part 9 (penetrations, transitions, and terminations) are most closely linked to common modular rigid coverings. Two other parts apply to swimming pools: Part 7 (waterproofing against water that exerts pressure from inside) and Part 6 (waterproofing against water that exerts pressure from outside) in buried basins and other underground s. Standard DIN (2000) presents a thorough classification of types of waterproofing based on the construction element involved, type of water, water action, and place where water occurs. That classification and the waterproofing materials then allow the design and requirements of the waterproofing system to be drawn up. The following tables summarise those contents [1]. [1] Source: Handbuch für das Estrich- und Belaggewerbe. Technik. VV.AA. Published by Rudolf Müller (Cologne, Germany), ISBN: Section 5.3, Tables 1, 2a and 2b. Waterproofing and drainage 1

2 Classification of types of waterproofing according to standard DIN in relation to water stress or solicitation and type of floor Nº Type of construction element 4 Type of water Incorporation situation Type of water action 2 Walls and base slab in contact with the Capillary water Contact damp Very permeable floor 8 3 ground above the water measurement Infiltration water > 10 4 m/s with drainage 1 level Less permeable floor m/s 5 Horizontal and Rainwater Balconies and similar sloping surfaces Infiltration water outdoors and in the Stagnant ground; surfaces of irrigation water 4 walls and floors in Service water without drainage 2 construction elements in housing construction Wet building areas 3 in housing construction 6 wet building areas 3 6 Roof surfaces that are used 5 Roofings with abundant green 4 Wet building areas (excluding housing construction) 6 Swimming pools Walls, and deck slabs in contact with the ground below the water measurement level 9 Construction elements that contain water, basins Underground water Flood water Roof surfaces that are not used, exposed to wind and weather, without a fixed service or wear layer, including those with abundant green Every type of floor, type of building, and form of construction Damp from the floor and non-stagnant infiltration water Stagnant infiltration water Water that exerts no pressure, moderate stress or solicitation Water that exerts no pressure, high stress or solicitation Water that exerts pressure from outside Service water Outdoors, and inside buildings Water that exerts pressure from inside Required type of waterproofing according to DIN Section 9 of DIN :2000 Section 8.2 of DIN :2000 Section 8.3 DIN :2000 DIN Section 9 of DIN :2000 DIN ) Drainage in accordance with standard DIN ) To foundations depths 3 m below the surface of the land, otherwise row 8 3) Definition of wet building area: internal building area with evacuation of floor water conditioned by use 4) To a stagnation height of about 10 cm with abundant green 5) For example roof decks, surfaces with abundant green, high-rise car park decks, patio cellar decks, and traffic areas subject to high stresses or solicitations by cleaning and service water, floor and wall surfaces in wet building areas, walkways or swimming pool surrounds, industrial kitchens 6) For example, balconies and similar surfaces in housing construction, floor and wall surfaces directly exposed to splashed water in wet building areas 7) Walkways or swimming pool surrounds, shower facilities 8) See standard DIN Waterproofing and drainage 2

3 Bitumen sheets Standard Designation Article Thickness Junction Type of overlap Bitumen sheet for fusion with non-woven glass-fibre interlining V mm 80 mm Sheets = loose Bitumen sheet for fusion with non-woven glass-fibre interlining and aluminium Bitumen sheet for fusion with fabric interlining Bitumen sheet for fusion with fabric interlining Bitumen-elastomer sheet for fusion with fabric interlining Bitumen-elastomer sheet for fusion with fabric interlining Bitumen-elastomer sheet for fusion with nonwoven polyester-fibre interlining V AL 4 mm 80 mm Sheets = loose G 200 S4 4 mm 80 mm Sheets = loose G 200 S5 5 mm 80 mm Sheets = loose PYE-G200 S4 4 mm 80 mm Sheets = loose PYE-G200 S5 5 mm 80 mm Sheets = loose PYE-PV 200 S5 5 mm 80 mm Sheets = loose Cold-adhered elastomer sheet KSK 2 4 mm 80 mm Sheets = Primer across the entire surface in accordance with the manufacturer s instructions Junctions = fulled Synthetic sheets Standard Designation Article Thickness Junction overlap Bitumen sheet with ethylene copolymer E.C.B mm Polyisobutylene sheet P.I.B mm Polyvinyl chloride soft compatible with bitumen Polyvinyl chloride soft incompatible with bitumen PVC. P mm PVC. P mm Type of 50 mm Sheets = loose 50 mm Sheets = loose Junctions = solvent 50 mm Sheets = loose Junctions = solvent 50 mm Sheets = loose Junctions = solvent Waterproofing and drainage 3

4 The standard also addresses the efficiency of the waterproofing materials in relation to their ability to close or restrict the passage of water vapour. The resistance to water vapour diffusion is expressed through the factor µ and the diffusion-equivalent air layer thickness S d, since µ expresses the number of times that a material is more resistant than air at the same thickness. S d = µ x S S d : Diffusion-equivalent air layer thickness, in m µ: Water vapour diffusion resistance factor S: Waterproofing layer thickness, in m In the case of waterproofing systems that receive screeds (as protection layers), other specialised layers and/or modular rigid coverings as finishes, the design rule is always observed that the waterproofing S d value must be higher than that of the overlying covering, and be the sum of the different S d values of the layers involved. The following tables provide the S d values for the waterproofing materials and for the materials that are part of outer layers, either as protection or finish. S d VALUES OF DIFFERENT WATERPROOFING MATERIALS Waterproofing materials in accordance with DIN Thickness Approx. S d value 1 (1) Bituminous waterproofing (fusion welded sheet) (2) Bituminous waterproofing 3 30 (brush-on emulsions) (3) Bituminous waterproofing 3 80 Polymer bitumen emulsions (brush-on emulsions) (4) Coarse bitumen covering modified with synthetic materials (5) Bituminous waterproofing (Elastomer sheet for fusion and cold self-adhering elastomer sheet (6) Asphalt mastic (7) EPDM sheets (8) Bituminous waterproofing with metal strengthening 4 (9) Waterproofing sheets of synthetic materials PVC (10) Waterproofing sheets of synthetic materials PVC Alternative waterproofing Thickness Approx. S d value 1 (11) Rigid waterproofing (slurries) (12) Dispersed synthetic resin waterproofing, Dispersed acrylate waterproofing (13) Semi-rigid waterproofing (elastomer slurries) (14) Synthetic resin waterproofing ) The most unfavourable value for the construction structure is the determining value. Source: [1] Waterproofing and drainage 4

5 S d VALUES OF COVERINGS OVERLYING THE WATERPROOFING Overlying coverings and auxiliary materials Thickness Approx. S d value 1 (0) 2 Adhesive + plasters (1) 3 Thin bed or intermediate bed (2) Punched non-woven fabric < 0.2 (3) Woven carpeting (4) Natural cork covering 2 6 < 0.2 (5) Carpeting with compact foam/woven back (6) Carpeting with TR back (7) 4 Installed, glazed or unglazed tiles (8) Parquet (9) Cork coverings, with a 0.3-mm layer (10) Linoleum (11) Laminate (12) Cushion vinyl (CV) coverings, (Top coverings with soft foam and waterproof mass) (13) Polyolefin (PO) coverings (14) Semi-flexible slabs (similar to mastic slabs) (15) PVC floor coverings (16) Rubber coverings (17) Synthetic resin layers ) The most unfavourable value for the construction structure is the determining value. 2) For overlying coverings that are adhered on top, it is always necessary to add the S d value of the adhesive and of the plaster material to the S d value of the covering. 3) For ceramic tiles fixed in an intermediate or thin bed, it is always necessary to add the S d value of the intermediate or thin bed to the S d value of the covering. 4) See the diagram: this depends on the joint proportion. Source: [1] In modular rigid coverings with impervious tiles, water vapour diffuses through the tile-to-tile joints (the same also occurs with glazed ceramic tiles, whether they are impervious or not). The water vapour diffusion resistance factor is deduced from the tile-to-tile joint surface area in relation to the total tiling surface area, and from the type of grout, from the graph shown: μ = grouting material μ joint proportion Waterproofing and drainage 5

6 S d is calculated from grout thickness S (tile thickness) and from the calculated µ [S d = µ x S]. To this, it is further necessary to add the S d value of the adhesive or bond mortar and, where appropriate, of the screed (floating floor screed as protection layer). For example, in a ceramic tiling with 200x200x10 mm glazed tiles and tile with 3-mm-wide open joints, the proportion of the joint grid in the total surface is: Proportion (%) = = % If a waterproof grout [µ=15] is used, the tiling water vapour diffusion resistance 15 factor will be about μ = 500, and with a grout thickness of 10 mm, S d = µ x S = x 0.01 m = 5 m. To this S d it is necessary to add the adhesive S d (S d = about 0.5 m for a 3-mm layer), so that the waterproofing S d will need to be larger than 5.5 m in order to observe the principle mentioned previously. Most standards and instruction sheets contain the following recommendations and conformity requirements: The waterproofing shall be installed under a minimum ambient and surface temperature of 5ºC The construction element that receives the waterproofing shall be dry, sound, well-cohered, level or with a regular slope, and also exhibit optimum flatness (without open cracks, cavities, and steps) In concrete floors that house s and ducts, where waterproofing against rising damp is planned, it is also recommendable to damp-proof the bottom of the channel before installing the pipes and the surface waterproofing [Figure 1] It is sufficient for the waterproofing system S d to be >200 m in order for the waterproofing, screeds, and tiling ensemble to perform well on exposure to water vapour diffusion. The consideration of systems that are waterproof to water vapour requires S d values >1500 m The waterproofing is assumed to be able to bridge crack formation to a certain extent (see chart). When those bounds are exceeded, a construction solution is required that decouples the waterproofing system from the underlying substrate. Waterproofing and drainage 6

7 MAXIMUM ADMISSIBLE CRACKING IN SHEET WATERPROOFING 0.5 mm wide when crack formation starts Maximum 2 mm wide at the end of the cracking process 1 mm maximum displacement of the crack edge with respect to the waterproofing plane In line with the foregoing point, the principle shall be observed that the waterproofing system cannot be assigned any transmission of forces, whatever their origin [instability of the underlying substrate, thermal oscillations, hydrostatic pressure caused by water build-up, etc.] Figure 1 Figure 2 It is vital to place water run-off and evacuation on top of the waterproofing. The normative references establish minimum slopes of 1% and most construction solutions include an appropriate drainage layer for the necessary evacuation. The insulation layers located under the waterproofing must be compatible with the requirements for stability and absence of stresses in the waterproofing system. In certain situations, this insulation requires of a barrier that closes the passage of water vapour towards the insulating layers [Figure 2]. Not only shall the surface run-off be assured, but so shall also the evacuation of the water that runs through the drainage or condenses on the layers on top of the waterproofing, which shall be appropriately connected to the drains [Figure 3]. Waterproofing and drainage 7

8 The junctures with abutting construction elements, from the alignment and slight curvature (about Ø 45 mm) of the right angles, up to the ascent of the waterproofing in outdoor terraces or wet internal building areas, also need to be carefully executed 2 [Figures 4, 5] As may be observed in the construction cross-section, both the condensation water, from the vapour migrating upwards through the deck and the slope layer, and the water filtering through the compression layer converge unhindered in the water drainage. 1. Ceramic tile 7. Soundproofing 2. Bonding material 8. Vapour barrier 3. Compression layer with reinforcement 9. Geotextile 4. Drainage (prefabricated system + geotextile) 10. Compressible material 5. Double layer of waterproofing 11. Soundproofing material 6. Thermal insulation Figure 3 Figure 4 Figure 5 2 The German documentation defines a wet building area as an internal building area in which the occurring quantity of water requires drains to be fitted in the floor. According to that concept, a dwelling bathroom is not considered a wet building area. Waterproofing and drainage 8

9 The choice of waterproofing system is also made as a function of the stresses to which the system will be subjected (in the case of flooring) and of the incidence/intensity of the action of water. Every standard and technical document offers a list of materials and requirements, including the number of layers, thickness of each layer, overlaps between sheets, join sealing, etc. Particularly to be noted is the information provided by the German standard DIN (2000) and the French standard NF DTU 43-6 (2007) [Parts 1-1 and 1-2]. In most construction solutions and all those that envisage drainage and a modular rigid covering as finish, sheet waterproofing requires the of a protecting layer, comprising a non-woven blanket and a mortar screed. The first layer serves to protect/decouple the waterproofing from the mortar screed that acts as a rigid protection element and base for the modular rigid covering. That is, a floating floor screed with the characteristics described in the section on screeds. systems require design and skilled labour. The specification must be accurate, with careful, and thorough control. The repercussions of non-quality in this part are of great importance. In most cases, one needs to work with subcontractors who will assure appropriate waterproofing and the subsequent satisfactory performance of the waterproofing. The informative document closes with key data, taken from the standards, on the materials involved in standard waterproofing, comprising the following sequence of layers: 1. Decoupling layer 2. Waterproofing and drainage 3. Protection layers Decoupling layer Blanket of (non-woven) glued glass fibres, with a minimum surface density of 100 g/m 2 [VV 100], whose mechanical characteristics are evaluated according to EN : (Longitudinal and transverse) tensile rupture strength 300 N/5 cm (Longitudinal and transverse) elongation in tensile rupture 1.2 % Tensile strength after water immersion (24 h and 50ºC) 210 N/5 cm Kraft paper of at least 70 g/m 2 EdsF paper (two sheets of 60 g/m 2 Kraft paper glued with 20 g/m 2 bitumen) Waterproofing and drainage 9

10 Waterproofing Those described in the initial tables. The (SBS) elastomer-modified asphalt sheets are governed by standard EN Protection Made up of a blanket or sheet and mortar or concrete screed, with the following characteristics: Non-woven geotextile or synthetic material of at least 170 g/m 2, which conforms to the requirements of standard EN ISO 9864 or, alternatively, a polyethylene film at least 100 µm thick. Cement or concrete mortar screed proportioned in 300 to 400 kg/m 3, water/cement ratio about 0.5, chosen from common cements of resistance class 32.5 MPa [EN 197-1]. Screed thickness never less than 50 mm, which increases as a function of service loads and, where appropriate, of insulation compressibility and thickness. These protection screeds on the waterproofing can be fitted with load distribution or strengthening reinforcement, whose mass shall be at least kg/m 2, electrowelded with a maximum mesh aperture of 100x100 mm. Screeds are handed over under the flatness conditions specified by the standards. Waterproofing and drainage 10