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zaubermaus8423 Oct 2018 21:42Hello everyone,
My partner and I are about to sign a contract for a plot of land with a developer. We specifically wanted a watertight concrete structure using waterproof concrete. However, we are having trouble understanding the construction specification. Could someone help us?
FOUNDATION SLAB
A reinforced concrete slab (thickness = 16cm (6.3 inches); steel reinforcement = 10kg/m2 (2.05 lbs/sq ft); concrete grade C25/30) will be constructed as the shallow foundation of the house and will include additional waterproofing against ground moisture according to DIN 18195-4. The flat-rate services from ACD also include a grounding strip made of galvanized steel band and a PE membrane laid as a cleanliness layer beneath the foundation slab. The foundation slab services in accordance with the building specification for the house are excluded.
INTERIOR AND EXTERIOR WALLS
The basement exterior walls exposed to air will be made from aerated concrete blocks, with wall thickness as specified in the drawings. The earth-contacting exterior walls will be constructed with concrete (thickness = 17.5cm (6.9 inches); steel reinforcement = 12kg/m2 (2.45 lbs/sq ft)) and insulated with 6cm (2.4 inches) of perimeter insulation (thermal conductivity class 040). Load-bearing and bracing interior walls will be constructed from aerated concrete blocks in the required thicknesses. Additional reinforcement for bracing the basement exterior walls may be required according to structural calculations. The clear height of the unfinished basement is 2.27 m (7.5 ft).
Waterproofing as specified in point 2
WATERPROOFING OF BASEMENT EXTERIOR WALLS
The exterior waterproofing of the basement walls protects against ground moisture. A drainage board or mat (e.g., Delta MS) safeguards the vertical moisture barrier during backfilling of the basement walls and ensures rapid drainage of water. This mat will be installed by the client as part of the backfilling work. All pipes passing through the basement exterior walls will be sealed. Basement window wells and a drainage system (e.g., drain pipes and flushing shafts) are not included. (Additional costs for waterproofing according to DIN 18533 class W2 or waterproof concrete guidelines may be necessary based on soil reports).
EARTH-CONTACTING EXTERIOR WALLS + EXTERIOR WALL INSULATION
The construction of the earth-contacting exterior walls follows point 1, using concrete. The perimeter insulation specified in point 1 is increased to 10cm (4 inches) (thermal conductivity class 040).
3. Additional waterproofing against hydrostatic pressure
The basement will be constructed with waterproofing against hydrostatic pressure (load case W2.1-E) as specified by the specialist planner. The waterproofing described in point 2 will be omitted.
My partner and I are about to sign a contract for a plot of land with a developer. We specifically wanted a watertight concrete structure using waterproof concrete. However, we are having trouble understanding the construction specification. Could someone help us?
FOUNDATION SLAB
A reinforced concrete slab (thickness = 16cm (6.3 inches); steel reinforcement = 10kg/m2 (2.05 lbs/sq ft); concrete grade C25/30) will be constructed as the shallow foundation of the house and will include additional waterproofing against ground moisture according to DIN 18195-4. The flat-rate services from ACD also include a grounding strip made of galvanized steel band and a PE membrane laid as a cleanliness layer beneath the foundation slab. The foundation slab services in accordance with the building specification for the house are excluded.
INTERIOR AND EXTERIOR WALLS
The basement exterior walls exposed to air will be made from aerated concrete blocks, with wall thickness as specified in the drawings. The earth-contacting exterior walls will be constructed with concrete (thickness = 17.5cm (6.9 inches); steel reinforcement = 12kg/m2 (2.45 lbs/sq ft)) and insulated with 6cm (2.4 inches) of perimeter insulation (thermal conductivity class 040). Load-bearing and bracing interior walls will be constructed from aerated concrete blocks in the required thicknesses. Additional reinforcement for bracing the basement exterior walls may be required according to structural calculations. The clear height of the unfinished basement is 2.27 m (7.5 ft).
Waterproofing as specified in point 2
WATERPROOFING OF BASEMENT EXTERIOR WALLS
The exterior waterproofing of the basement walls protects against ground moisture. A drainage board or mat (e.g., Delta MS) safeguards the vertical moisture barrier during backfilling of the basement walls and ensures rapid drainage of water. This mat will be installed by the client as part of the backfilling work. All pipes passing through the basement exterior walls will be sealed. Basement window wells and a drainage system (e.g., drain pipes and flushing shafts) are not included. (Additional costs for waterproofing according to DIN 18533 class W2 or waterproof concrete guidelines may be necessary based on soil reports).
EARTH-CONTACTING EXTERIOR WALLS + EXTERIOR WALL INSULATION
The construction of the earth-contacting exterior walls follows point 1, using concrete. The perimeter insulation specified in point 1 is increased to 10cm (4 inches) (thermal conductivity class 040).
3. Additional waterproofing against hydrostatic pressure
The basement will be constructed with waterproofing against hydrostatic pressure (load case W2.1-E) as specified by the specialist planner. The waterproofing described in point 2 will be omitted.
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zaubermaus8424 Oct 2018 10:19What would a proper scope of work description for construction look like?
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Mottenhausen24 Oct 2018 10:40The description is quite clear: by default, only the following are included:
“Protection against ground moisture” is not the same as a tanked basement, but if done properly, it is just as watertight as a tanked basement, because in practice there is only “sealed” or “not sealed,” regardless of what the standards say. But that is another topic.
However, you also received the following additional service in your offer:
So basically a floating boat. Everything is fine in my opinion. But the same applies here: if performed without expertise and, for example, when attaching plastic basement shafts the tanked basement membrane is punctured again, you may end up with water stains in the basement. Because waterproof concrete (WU concrete) alone (without an external coating) does not fully live up to its name.
zaubermaus84 schrieb:
FOUNDATION SLAB
...protection against ground moisture...
WATERPROOFING OF EXTERIOR BASEMENT WALLS
...external waterproofing... is done against ground moisture... Additional work for waterproofing... may become necessary
“Protection against ground moisture” is not the same as a tanked basement, but if done properly, it is just as watertight as a tanked basement, because in practice there is only “sealed” or “not sealed,” regardless of what the standards say. But that is another topic.
However, you also received the following additional service in your offer:
zaubermaus84 schrieb:
3. Additional waterproofing against hydrostatic pressure
Construction of the basement with waterproofing against hydrostatic pressure
So basically a floating boat. Everything is fine in my opinion. But the same applies here: if performed without expertise and, for example, when attaching plastic basement shafts the tanked basement membrane is punctured again, you may end up with water stains in the basement. Because waterproof concrete (WU concrete) alone (without an external coating) does not fully live up to its name.
Lumpi_LE schrieb:
There is no mention of a waterproof concrete shell or WU concrete here. Actually, there is a waterproof concrete shell...
Point 1: Aerated concrete blocks against ground moisture.
Point 3: Exterior walls in contact with the ground + exterior wall insulation
Construction of the exterior walls in contact with the ground according to Point 1 in concrete. Reinforcement of the perimeter insulation according to Point 1 to 10cm (WLG 040).
3. Additional waterproofing against groundwater pressure
Construction of the basement with waterproofing against groundwater pressure (load case W2.1-E) as specified by the specialist planner. The waterproofing according to Point 2 is omitted.
Someone must have copied text blocks together... however, the structure of the exterior wall is not clear to me. Is it now poured in WU concrete or just built with aerated concrete blocks and later waterproofed? I assume the former since it also states:
zaubermaus84 schrieb:
the exterior walls in contact with the ground made of concrete (d = 17.5cm (7 inches); steel reinforcement = 12kg/m2)Z
zaubermaus8424 Oct 2018 11:29I copied it exactly as it appears in the scope of work description. The problem is that it says "item 2 is omitted." The foundation slab is described, but in the last sentence, it says it is omitted. The description should specify that it is made of watertight reinforced concrete.
Isn't a "white tank" made of WU concrete, which does not require additional waterproofing, or am I misunderstanding this? Or does it also get a bituminous coating?
What do you think the description should say instead?
Isn't a "white tank" made of WU concrete, which does not require additional waterproofing, or am I misunderstanding this? Or does it also get a bituminous coating?
What do you think the description should say instead?
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