Fig. 1: Illustration of a building wall with service lines
Basic information on building waterproofing
In general, supply to and disposal from a building is implemented using service lines laid underground. The building shell needs to be penetrated in order to introduce these lines into the building.
In turn, the building shell is provided with waterproofing to protect the people, objects and of course the building itself against external influences, and especially penetrating water. This means that the building entry also penetrates the waterproofing.
It is possible to provide a gastight and watertight transition between the building waterproofing and the service line using an appropriate sealing system, also known as a entry system. This reinstates the building waterproofing. The building waterproofing, and therefore also the entry system, is logically located on the outside of the building, which means that access to the entry system is often extremely restricted or even no longer possible. This means that a large proportion of all entry systems have to function without maintenance. Depending on the building usage the lifespan of the building, and therefore also of the entry system, can be up to 50 years. This makes the high quality requirements on entries systems obvious.
Fig. 2: Soil moisture
Fig. 3: Non-standing seepage water
Fig. 4: Temporary standing seepage water
Fig. 5: Pressing water
2. Load cases in structures contacting the ground
Definition, determination, influencing factors
The type and method of building waterproofing is dependent on the load case acting on the building.
The designer decides which load case is acting by calculating the design water levels (highest groundwater level to be expected +30 cm safety factor). Normally, a minimum period of between 20 and 30 years is assumed in this case. On top of this, the water management influencing factors should also be taken into account. Irrespective of these, changes (height increases) to the moisture load can still occur, for example caused by:
- extreme weather conditions with high precipitation levels,
- increase in groundwater levels through reconditioning work to sewage lines,
- surface sealing,
- soil substance (e.g. mining areas) or
- water management influencing factors (e.g. shutting down of pumps).
DIN 18195 describes the following load cases which are described below in more detail:
2.1 Soil moisture and non-standing seepage water
Soil moisture is understood to be capillary-bound water which is also capable of moving against the forces of gravity due to capillary forces present in the soil (suction water, retained water, capillary water). However, non-standing seepage water from rainfall is also included in the case of vertical wall elements. A requirement for the above is a strongly permeable soil (sand, gravel, with a water permeability coefficient of k > 10-4 m/s or a permanently-functioning drainage system in acc. w. DIN 4095.
2.2 Non-pressing water
Non-pressing water is understood to be water in drop and liquid form which does not exert, or exerts very little, hydrostatic pressure onto the waterproofing (precipitation, seepage or process water). This applies to the waterproofing of horizontal and inclined surfaces in addition to wet areas (e.g. baths with floor drainage) with irrigation heads of up to 100 mm (under greened roofs). This means that it is not used for external walls in contact with soil.
2.3 Temporarily standing seepage water
Standing seepage water is understood to be water which exerts a temporary hydrostatic pressure.
2.4 Pressing water
Pressing water is understood to be water which exerts a permanent hydrostatic pressure.
Table: Recommended minimum structural component thicknesses (information in mm) 
|No.||Structural element||Load Class||1||2||3|
|In-situ concrete||Element walls||Precast elements|
|1 Loading Class 1: Pressing and non-pressing water in addition to temporary standing seepage water.
2 Loading Class 2: soil moisture and non-standing seepage water.
3 Reduction down to 200 mm is possible under the implementation of special concrete and implementation measures.
Fig. 6: Working model for moisture conditions in a concrete componentcross-section with one-sided application of pressing water(concrete C30/37 (B35 water-impermeable) w/c ≤ 0.55) basedon Beddoe / Springenschmid
3. Types of structural waterproofing
3.1 White tank. Water-impermeable structures in concrete (water-impermeable concrete)
The construction of entries in water-impermeable structures made of concrete is regulated by the DAfStb Guideline – Water- impermeable Structures in Concrete issued by the German Committee for Reinforced Concrete. In general linguistic use these building waterproofing systems are known as a “white tank”. The guideline specifies the following with regard to entries:
“All structural joints and entries must basically be designed and implemented as waterproof with suitably adapted systems depending on the loading class.”
The WI Guideline differentiates between two loading classes:
Class 1: pressing and non-pressing water in addition to temporarily standing seepage water
Class 2: soil moisture and non-standing seepage water
There is little information about the implementation of entries, and also few definitions of requirements.
The wall thicknesses are specified depending on the expected water loading (immersion depth) and from the concrete quality (crack sizes and crack frequency).
In this type of building waterproofing it should be noted that this type of building consists of not a waterproof but rather a waterimpermeable wall structure. Water in the form of pressing water can penetrate up to 25 mm into the concrete over its full area.
On top of this, the water can penetrate maximum 70 mm intothe existing capillaries. Water can defuse up to 80 mm into orout of the wall on the wall weather side depending on the moistureconditions.
A core area which prevents water transport from the water sideto the air side (water impermeability) can only be formed if awall thickness of ≥ 200 mm (depending on concrete quality,grain size, reinforcement cover etc.) is chosen. For this reason,the entry system must be provided with a sealing area width appropriateto the load case.
Furthermore, it should be installed on the side of the wall facingthe water so that the water cannot penetrate the wall deeperand therefore so that the core area is lost.
When constructing the apertures for entries using core drillings,the reinforcement is cut. This can result in cracks. These crackshave to be repaired before installing the entry systems, and anyreinforcing steel uncovered in this manner must be protectedagainst corrosion. This means that the use of pipe sleeves isexplicitly recommended. Normally, pipe sleeves are concreted inwhen constructing the structural element.
Entries, and especially the apertures for their use, may never belocated on construction joints. A distance of ≥ 300 mm isrecommended.
Fig. 7a: Sealing layer precast element
Fig. 7b: Sealing layer in-situ concrete
Fig. 7c: Covering sealing system
3.1.1 Element walls
Element walls represent a combination of precast concreteelements and in-situ concrete. In this case, two precast segmentsare separated by lattice beams, and the void betweenthem is concreted in with in-situ concrete. The requirements andthe measures to be taken are regulated in the WI Guideline.Such entry systems should be positioned in the sealing layer.
This is generally the in-situ concrete. If surface sealing systemsor special versions of precast concrete segments are used, thesystems can also be located in the outer surface. In this case,clarification with the planner or constructor of the wall is necessaryin advance. In cases of doubt, special entry systems whichcover all the sealing layers can be used.
3.2 Black tank
Waterproofing of non-waterproof structures
Penetration of the waterproofing in structural segments in contactwith soil for cable and pipe entries is mostly regulated byDIN 18195. DIN 18195’s scope is related to the waterproofingof non-waterproof structures or structural segments. The arrangementand implementation of entries is especially regulatedby DIN 18195-9. Building waterproofing of this type is generallyknown as a “black tank”.
Entries must be planned and implemented so that they cannotbe run round or under, if necessary with the help of installationcomponents. The constructive and waterproofing measures necessaryfor this purpose must be adapted to the expected waterloading .
The entry must be located so that the structural waterproofingcan be professionally closed off. Components requiring maintenancemust be located and further layers must be designed sothat simple accessibility is guaranteed . The edges of the entrysystem must be free of burrs.
External edges of the connecting elements of glued and weldedflanges in addition to collar constructions should normally be atleast 150 mm from structural element edges and structural elementfillets, and at least 300 mm from structural joints. In casesof loose and fixed flange structures, the distance should be atleast 300 mm from structural element edges and structural elementfillets, and at least 500 mm from structural joints. If thesedistances cannot be adhered to, special structures must beplanned.
Entries may not lose their function if the structural component oradjacent soil layers carry out expected movements, if necessaryspecial measures must be taken in such cases (proper compaction,footings made of lean concrete etc.).
Fig. 8: Tanking membrane with packing (Curaflex® C/2/SD/5)
Fig. 9: Example of fixed/loose flange structure
3.2.2 Entry implementation
The following entry systems are to be used depending on the load case:
18.104.22.168 With the use of tanking membranes
a) Soil moisture and non-standing seepage water
With this load case, the waterproofing is to be connected to theentry with the aid of a bonding flange, a welding flange or acollar with a clamp. The flange width for bonding and weldingflange structures must be between 80 mm and 120 mm dependingon the waterproofing material.
b) Non-pressing water
With this load case, the waterproofing is to be connected to theentry with the aid of a bonding flange, a welding flange, a collarwith a clamp or a loose and fixed flange structure.The loose and fixed flange structure must be made of steel andhave the following dimensions:
- loose flange width min. 60 mm
- fixed flange width min. 70 mm
- material thickness min. 6 mm
- tensioning bolt or tensioning screws min. M12 with a spacing of between 75 and 150 mm.
The torques with which the construction is to be tightened arespecified in DIN 18195 Part 9 depending on the type of tankingmembranes used. In cases of doubt these must be requestedfrom the manufacturer of the tanking membranes.
When bitumen tanking membranes is used, a steel ring for preventionof bitumen outflow is to be provided. In the area aroundflanges, the tanking membranes may not have any faults, kinksor other uneven features. DIN 18195 also requires packingsconstructed of the same material or material-compatible elastomerson both sides in the case of single-layer, loosely-laid waterproofing.
Practice has shown that thin and/or hard tanking membranescannot be sealed off properly without packings.
c) Temporarily standing seepage water and pressing water
The waterproofing is to be connected to the entry with the aid ofa loose and fixed flange structure for this load case.The loose and fixed flange structure must be made of steel andhave the following dimensions:
- loose flange width min. 150 mm
- fixed flange width min. 160 mm
- material thickness min. 10 mm
- tightening bolts or screws min. M20 with a spacing of between 75 and 150 mm
The requirements or specifications with regard to torques, limitationsagainst outflow of bitumen, condition of tanking membranesin the area around the flange and packings applyanalog in this case.
Fig. 11: Pipe sleeve system with bonding flange (Curaflex® 3001)
22.214.171.124 With the use of plastic-modified bituminous thick-coating
If waterproofing in the form of trowelable plastic-modified bitumenwaterproof coatings has been applied, the entry can be implementedas follows depending on the load case:
a) Soil moisture and non-standing seepage water
For this load case, the plastic-modified bituminous thick-coating(PMB) can be trowelled on to the entry in the form of a fillet.This implementation variation is only permissible if the serviceline or pipe sleeve is not expected to be subjected to any axialor radial movements over the entire service life. It may be necessaryto roughen the surface in order to achieve sufficientbonding to the service line. This must be agreed in advance withthe service line operator or constructor. Since this option canseldom be guaranteed in practice, implementation using abonding flange is recommended.
Fig. 10: Towelling of fillet type 
b) Non-pressing water
In this load case, the plastic-modified bituminous thick-coating(PMB) must be applied to a bonding flange using reinforcing inserts,or connected to a loose and fixed flange structure.
Fig. 13: DOYMA Curaflex® 1776
c) Temporary standing seepage water
A prefabricated installation component made of a bitumencompatibleplastic tanking membranes must be clamped in aloose and fixed flange structure for this load case.In the connection area around the plastic-modified bituminousthick-coating (PMB) this waterproofing sheet must be providedwith a fleece or fabric backing in which the plastic-modified bituminousthick-coating (PMB) can be bedded.
Fig. 12: Connection of PMB to loose and fixed flange structure 
Such installation components made of tanking membranes are difficult to obtain in normal trade. Other solutions, such as the DOYMA Curaflex® 1776, have proven themselves in this situation.
d) Pressing water
According to DIN 18195, this load case is not permitted forplastic-modified bituminous thick-coating (PMB). However, thisprocedure is recommended by the manufacturers of plasticmodifiedbituminous thick-coating (PMB) and the “Verband derDeutschen Bauchemie”, and should be carried out using a looseand fixed flange structure.
Fig. 14 a: Support with suspension mechanics and sliding element
Fig. 14 b: Support with suspension mechanics
Fig. 14 c: Support with side mechanics
4. Support and service line movements
Basic fixing methods
Annular gap seals in the form of compression seals can not absorbradial movements in normal cases. In this case, they maynot be used as bearings.
The service lines must be appropriately supported. A range offitting systems are used to absorb such support forces.
These fitting systems can be fixed directly in front of and behindthe wall entry. If fitting to the wall is not possible for static or waterproofingreasons, a support made of lean concrete can beconstructed in front of the wall, for example.
If axial movements are expected in the service lines, special fittingsystems with appropriate slide elements and guide supportscan be used.
Fig. 15 a: Axial displacement
Fig. 15 b: Angling
Fig. 15 c: Lateral movement
Fig. 15 d: Settlement
4.2 Service line movements
Possible service line movements in sealing insert
Movement in the direction of the service line axis/longitudinal axis.
Gasket inserts can sometimes absorb these movements.
Inclination of pipe axis: The pivot point must be in the centre ofthe sealing insert. Gasket inserts can sometimes absorb thesemovements. It is imperative that clarification is carried out withprofessional experts for each individual case.
Sideways displacement of service line (radial movement) Thesealing insert is not capable of absorbing sideways displacement.For this reason this type of movement must be ruled out.
Building settlement can lead to the displacement or twisting ofpipes. Displacement or twisting cannot be absorbed by the sealinginsert. For this reason, displacement must be ruled out structurally.
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