Can I do my own BW plans for attic ensuite?

[Richard C]

I would really advise you check the status of the conversion with LABC. If it is unauthorised you will only compound the problem by putting an en-suite up there & it may come back to bite you in the future. If it’s been authorised or is authorised by nature of time default then you’re OK but constructing a new room with a w/c up there will require a Building Notice submission & inspection which will highlight the status of the current conversion in any case.

 

[DevilDamo]

My personal opinion is to just submit a Building Reg's (Building Notice) application for the installation of an en-suite and be done with it.

 

[dagoof]

Ok, just spoke to a helpful lady at the local building control and have some good news (I'm sure you're all on the edge of your seats ). The previous owner hadn't applied for any plans etc but were concerned about this when selling so had consulted BC who had inspected & granted them a 'note of comfort'. I'm assuming this is a Scottish thing but the lady told us that this means the council have approved it and have no concern over it, and further, that it doesn't influence us in applying for a BW for the ensuite (so basically we have a blank slate!).

So, as far as I can tell, the only issue we have to get around now is the drainage.

 

[DevilDamo]

That's good then Better to be safe than sorry. If there were to be any problems or implications, I would have thought it would have been via Building Control and not Planning.

 

[Richard C]

Good result so it was worth checking.

Just to be clear; my only concern about planning was based on the size of the conversion if you had to re-submit as there are limitations on the volume to remain inside permitted development; in England anyway.

 

[DevilDamo]

Yeh, 40 cu.m and 50 cu.m

 

[dagoof]

No problem, was just prudent to check, I understand.

Regarding drainage, a friends brother told me the following:
you need to check what fall, might get away with a 1:150 fall depending on the size of the pipe (a drawing should tell you). Some falls have to be 1:80 or 1:40 though which would be a problem. Yes, you should really have an AAV which you can hide but it must be accessible and 300mm above flood height - its' instead of sticking a soil vent pipe thru your roof or, as in ur case, 6m from the external svp. Other option might be a macirator, like a poo chopper which pumps the crap thru a smaller pipe...nice.

Cmments?

So would the fall height be measured 'sub-floor' or from the toilet's output (e.g. 6" above the floor)? Also, with the AAV, does this need to run straight above the toilet? I ask because the WC is below the lowest point of the pitched roof - if it did need to go straight above the WC then it'd need to go through the roof anyway. If not, could the vent pipe be run diagonally up the pitched roof and vent at a higher point?

 

[Richard C]

you need to check what fall, might get away with a 1:150 fall depending on the size of the pipe (a drawing should tell you). Some falls have to be 1:80 or 1:40 though which would be a problem.

Minimum fall for a w/c soil pipe is 18mm/m which equates to 1:55; maximum gradients on baths/wash basins etc vary but all are also 18mm/m up to 90mm/m

Yes, you should really have an AAV which you can hide but it must be accessible and 300mm above flood height - its' instead of sticking a soil vent pipe thru your roof or, as in ur case, 6m from the external svp.

Mostly correct; you can only fit an AAAV if you have another open stack on the system which will cater for positive ass well as negative pressures which an AAAV can’t do, otherwise you’d get all those nasty smells. Regarding the valve mounting height; it must obviously be fitted above the highest waste flood point (usually the top of the wash basin) but the although a reference of 300mm above the flood height is regularly mentioned, as far as I’m aware there is no such requirement, it just has to be above the highest spillover point.

You should also consider that if teeing into the 110mm w/c line with shower/sink waste & depending on layout, your other appliances will probably need venting or fitted with anti-siphon traps.

Other option might be a macirator, like a poo chopper which pumps the crap thru a smaller pipe...nice.

As I said, to be avoided at all costs unless there is no other option. Not so much of a problem if your responsible about what you put down there & don’t have any kids but I’ll leave you to imaging what a pleasant job clearing a blockage in one would be!

So would the fall height be measured 'sub-floor' or from the toilet's output (e.g. 6" above the floor)?

The fall is measured over the length of the pipe; i.e. the pipe must fall 18mm for each 1 metre length; the vertical drop from the w/c is irrelevant.

Also, with the AAV, does this need to run straight above the toilet? I ask because the WC is below the lowest point of the pitched roof - if it did need to go straight above the WC then it'd need to go through the roof anyway. If not, could the vent pipe be run diagonally up the pitched roof and vent at a higher point?

The vent stack can go at any angle you want, its sole purpose is to let in air. The AAAV must also be fitted above the highest flood line, accessible & the actual bit of pipe it’s fitted to must be vertical or it won’t vent properly.

Download the PDF "Design Criteria"; http://www.hunterplastics.co.uk/content/1/94/soil---waste-support.html
I've posted this link so many times now, I’m worried folks might think I’ve got some connection For the record, I haven’t it's just I think it’s a really useful little guide which is easy to understand & includes BR requirements.

 

[dagoof]

Thanks again for that info Richard - I had the plumber back for a more in-depth consult today and, as you had mentioned, we discussed the possibility of putting in a new soil pipe. We decided this would be the best option, running towards the front of the house, where there's only 2-3m of run (also going to use a shower tray with riser kit).

Something else which was surprising, phoned the BC this morning to talk about running plans by them - they said, as it's a bungalow, as long as we're not trying to create new floor space or removing any load bearing partitions, then we don't even need a building warrant! He said the only thing we'd need a warrant for was if rafters had to be cut for a velux (and obviously that we'd need to do everything to current BR spec).

 

[DevilDamo]

I wasn't aware you had a chalet bungalow?

So the BC department are not fussed you're going to be installing new drainage, ventilation, etc... for this en-suite?

You mentioned you're going to be installing a new velux and if your existing (trussed) rafters are at 600mm c/c then you should be able to get a decent size velux to fit between, without having to mess around with the existing roof structure. However, if you're existing rafters are at 400mm c/c, then getting a velux to fit between is a little more difficult, which would result in the existing roof structure being adapted to suit. The BC department may even ask for structural calculations to justify any additional support you provide (i.e. doubling up below, above and either side of the new opening).

 

[dagoof]

Yeah, it's just a little end-terraced bungalow Damian - they said we didn't need to submit/approve anything (other than the window where applicable), but just to do it to current regs.

The rafters are the 400mm unfortunately - I'm on google just now trying to see what I can get but I suppose by the time the frame's come into play it's not leaving much window!

 

[DevilDamo]

Have you considered a sunpipe? They're normally used where you have a ceiling but I'm sure they can be used on a skeiling? You can get those in small diameters and they do provide a good amount of light, but they're not openable like velux's are.

Do you "need" a window in the en-suite? It depends whether you want to go through the hassle of having calculations done and then getting BC involved as you'd be making structural alterations.

 

[noseall]

they said we didn't need to submit/approve anything........................... but just to do it to current regs.

I take it you do know how to build things to current reg's then?

Based upon what i can gather from this thread, you seem to have interpreted "current building regs" rather conveniently to fit the work you have already carried out, whether it complies or not.

The idea is to make the works compliant to the (current) reg's.

.....or is it me being cranky because i have ANOTHER cold.

 

[hotrod]

.....or is it me being cranky because i have ANOTHER cold.

I don't know Nose, but if you keep getting colds/flu get some of these* down yer:-

*Other brands are available

 

[dagoof]

I take it you do know how to build things to current reg's then?

I do now

But seriously, thanks to users here, the architect and the plumber I think I've got most areas covered. And I haven't done any work yet so not sure what you mean

But, yes, it does seem an odd thing for them to say when they don't have any interest/intention of enforcing it!