19 - Case Study Questions Flashcards
Q. who specified the product? Including the sump pump?
A. I provided the specification for the cavity membrane system ensuring all corners (floor and wall) had the seal tape. Ensure the gutter channel had an upstand that would fit with the studded membrane. Also ensuring the drainage channel connected to the drainage outlet and into the sump chamber with pumps.
Q. what type of pump did you specify?
A. a submersible pump which is completely mounted inside the sump as the client didn’t want it to be visually noticeable and out the way as it was a tight space. I considered the size of the pump to ensure the concrete floor foundation will be cut out deep enough to take the pump. Pump storage capacity 100l. the capacity to pump out 1000 lph.
Q. how long can a sump pump run for?
A. a good quality pump can run for an average of 20-24 hours straight. Obviously if it runs for this period of time there is a wider issue and will wear the pump out quickly.
Q. describe the main components of the tanking system?
A. includes: studded wall and membrane, quick seal plugs, gutter channel, the electric pump with high water level alarm (battery operated uses a standard 9V PP3 battery, loud 90dB alarm),
Q. what is the difference between render and slurry system?
A. slurry is a mixture of cements, aggregates and chemicals that when combined can become permeable. The chemicals and aggregates in the slurry improve the strength and bonding in a way that ordinary cement is not. It comes in powder form and requires mixing. Requires a minimum of two coats to be effective. Can be applied by trowel, brush or spray.
Render – something like SIKA render system consisting of cement and add-mixture. It bonds to the substrate
Q. how would you check that the contractor is best suited for the job at hand?
A. I ensured the contractors that the tender is going out to hold the relevant qualifications, such as CSSW (Certified Surveyor of Structural Waterproofing). I also ensured all tanking works comes with a minimum 10 year guarantee for the works to give my client a complete piece of mind.
Q. Talk me through the initial desk top risk assessment that you undertook prior to your initial site inspection? (Assuming of course you needed to do this - however it’s always useful to know the answer to this question even if you didn’t do it on this occasion).
TBC
Q. why didn’t you just use a SIKA damp proof slurry?
A. it was considered at the time and if I had recommended this option SIKA would be someone I would mention. However considering the amount of water coming into the building it isn’t the most appropriate method, although the cheapest and quickest in time.
Q. name some legislation documents you may refer to for further information on tanking below ground?
A. the main document I referred is BS8102:2009 to understand the types of waterproofing methods available considering the construction of the basement. This highlights there are 3 types of waterproofing A (barrier protection), B (structurally integral protection and C (drained protection).
I also referred to AD Part C (Site Preparation and Resistance to Contaminants and Moisture) for advising on improving the ventilation to the front basement void space. This is to help naturally reduce the condensation that I noted to the underside of the timber floor.
Q. Explain how the membrane system is installed?
I specified a type c (drained protection) membrane system in the following method:application of the studded membrane to the wall (studs side facing the wall/substrate)
2 - 10 mm diameter holes are drilled through the membrane, drill hole spacings as per manufactures instructions.
3 - quick seal plugs are driven in the holes, the integral pre-formed grommet provides an effective seal between the head of each plug and the membrane
4 - drainage channel is installed in base of the channel chases using connecting pieces, clean washed stones can be installed if required.
5 - a floor studded drainage membrane is placed on the floor, butted up against the upstand of the drainage channel. Corner strip tape is applied to seal the wall and floor membranes together.
6 – insulation will be placed on the floor membrane with a timber floating floor on top of the insulation.
7 – treated timber battens (or metal frame) will be screwed into the quick seal plugs, the design of this to be coordinated with any fixings such as shelving to go onto the walls.
8 – plasterboard to be mechanically fixed to the timber battens.
