Feel free to mock me for my lack of knowledge, but if you can provide any advice whatsoever, it would be most appreciated as I want to learn which is why I'm asking these questions!
When laying a waste pipe in concrete ground floor as a retrofit (for e.g. a shower tray), I can see see potential for problems, mostly related to the damp proof membrane getting damaged.
As an example, when rectifying a lack of ventilation to a part of my ground floor at my home (known as "Bodge Central"), I discovered that in the porch, the DPM was between the 2" screed and the concrete below. But in my lounge extension, it was below the concrete base (no sand between the plastic and concrete), but someone thought two bits of thin plastic were as good as a single thick sheet so the DPM was easily damaged. In the end I took a road breaker to the lounge floor and put in suspended timber.
When trying to keep a job contained, such as in a customer's house, how would you go about this? Obviously you'd only need to remove the screed plus a proportion of the concrete to get sufficient clearance for a 40mm waste (wrapped in felt?) plus any required fall... I think.
I'd imagine a Kango rather than a road breaker so as to chip up only what is required using a grinder to help if need be, lay the pipe to an even gradient, wrap it in something to allow expansion?, allow for access, pressure test, and backfill with a weak mix.
If the DPM turns out to be just below the screed though... but perhaps that only happens in very amateur situations where building control is not involved?
I'm a bit lost, and I'd like to know what people consider the right way as I see too much of this sort of thing done wrong.
When laying a waste pipe in concrete ground floor as a retrofit (for e.g. a shower tray), I can see see potential for problems, mostly related to the damp proof membrane getting damaged.
As an example, when rectifying a lack of ventilation to a part of my ground floor at my home (known as "Bodge Central"), I discovered that in the porch, the DPM was between the 2" screed and the concrete below. But in my lounge extension, it was below the concrete base (no sand between the plastic and concrete), but someone thought two bits of thin plastic were as good as a single thick sheet so the DPM was easily damaged. In the end I took a road breaker to the lounge floor and put in suspended timber.
When trying to keep a job contained, such as in a customer's house, how would you go about this? Obviously you'd only need to remove the screed plus a proportion of the concrete to get sufficient clearance for a 40mm waste (wrapped in felt?) plus any required fall... I think.
I'd imagine a Kango rather than a road breaker so as to chip up only what is required using a grinder to help if need be, lay the pipe to an even gradient, wrap it in something to allow expansion?, allow for access, pressure test, and backfill with a weak mix.
If the DPM turns out to be just below the screed though... but perhaps that only happens in very amateur situations where building control is not involved?
I'm a bit lost, and I'd like to know what people consider the right way as I see too much of this sort of thing done wrong.
