Ensuite Stud Wall - Sole Plate on Joists or Floorboards?

[Richard C]

If I was not to use separate waste runs to the mail stack how would I go about connecting them, would they need to be fed into the horizontal w/c pipe?

Thinking about it again, diving straight through the wall with the toilet waste will mean it will be too high to connect the shower/sink waste. You may end up with a separate stack connection for the shower/sink or run the w/c outlet through a bend either inside or outside rather than straight so you can tee into it; it will need some further thought once you have a decent scale drawing.

Thanks for that, I just thought an opening window would suffice!

Afraid not.

Im unsure how old the consumer unit is. The master bedroom (where the ensuite is being added) was built in the 80s, so the wiring is probably over 20 years old.

Older properties (such as mine) weren’t built with earthed lighting circuits; I don’t know when earthing became mandatory but yours will almost certainly be OK. A 20 year old consumer unit may give problems as it probably won’t comply with current regulations & may have to be changed/upgraded to a modern breaker/RCD unit. I would advise you consult a qualified sparky for advice early on as you may find they wont connect you new bathroom circuits into the current consumer unit. My property is 40 years old & I ended up having to have a new consumer unit, earth bonding & a rewire of most of the lighting circuits; entirely necessary but my wallet said ouch!

The ensuite will be built ajoining an original external wall on one side (brick/block cavity that was originally the outside of the house). I assume then I don’t have to sound insulate this section of wall (behind which is a bedroom)?

No.

I was planning on using soundblock on the outside of the studs (bedroom side) and moister resistant plasterboard on the inside (with aqua panel for the shower enclosure) and then sound insulate the studs.

If it’s just the walls forming the en-suit inside you bedroom then you don’t have sound insulate (or any wall with a door in it) but if you want to that’s fine. If sound insulation was required, MR board won’t meet the spec. but as it’s not then MR is good. Use 12mm square edge boards not taper edge, you can get them but may have to search around a bit. Its best not to plaster the boards where you’re tiling just stick the tiles straight onto the boards; MR will need priming. Also if you want to plaster MR board, it must be primed first but if you’re using a spread he should know that anyway.

Knauf Aquapanel is good for the shower enclosure but fill & tape the joins. Knauf do a purpose made sealer but some use Silicone; not much will stick to silicone (including tile adhesive) so I don’t use it here; be careful if you decide to, don’t get it all over the face of the board. Make sure joints in the Aquapanel don’t coincide with any grout lines in the tiles for obvious reasons. Run the Aquapanel just outside the shower enclosure & extend the tiles over where it joins the PB. I plaster before tiling & just waste the skim slightly into the tiled areas so you’re left with a nicely plastered wall after tiling.

 

[chapeau]

What a cracking few posts by Richard C, going in my bookmarks this one is!

 

[watsite]

I'll second that, thanks again Richard this advise will be invaluable to my future project.

As promised her are some plans to scale of the proposed ensuite and some 3D mock-ups.

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[Richard C]

Few questions;
You show a doorway in what appears to be the outside wall of the adjacent room, is this the ground floor of a bungalow?
Which direction do the floor joists run?
Have a look around outside for inspection covers; if there are any, can you show the relative locations on your sketch?
In which direction is the main road?

 

[watsite]

Hey Rich,

Sorry for the late reply, this is the first chance all weekend i've had free to get online!

You show a doorway in what appears to be the outside wall of the adjacent room, is this the ground floor of a bungalow?

i've just read my last post and realised I didn't give enough detail about the plans. Then master bedroom is on the second floor and the room modelled next to it is a walktrough bedroom; i am aiming to model the whole house but as yet haven't found the time.

Which direction do the floor joists run?

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Have a look around outside for inspection covers; if there are any, can you show the relative locations on your sketch?

I will aim to mark these on the full house diagram to be posted soon.

In which direction is the main road?

In the diagrams on my previous posts the main road on the opposite side of the house from the master bedroom (will be made clearer on new diagrams)

 

[watsite]

OK, so here are the images as promised. The 3d image shows the house with the existing soil stack in black and the proposed horizontal soil run in blue.

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The following image shows the plan of the first floor of the house, and shows the side the road runs on and drain access.

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[Richard C]

The sink should be fairly straight forward; you can either run along the wall above the floor & drop down into the floor between the joists or run on the cieling below. The shower waste runs across the joists so your either going to have to drop through the ceiling & box it in below; this can look OK as in my case or look totally naff, it rather depends on the layout of the room below; do you have a layout showing the ground floor below? Another solution is to go out through the wall & run the waste along the outside. This may give you problems with the length of run & won’t look particularly nice on the outside as it will also have to dive around the corner before connecting to the main 110mm run; do not contemplate cutting/notching the joists! There is also how you tie it all together; run a stub stack inside down into the room below before diving out through the wall & onto the existing stack but would involve boxing in the room below; straight out through the wall & down so you can connect it all up on the outside (looks messy outside). To give you some ideas on what’s possible, have a look at this guide which also incorporates necessary Building Regulations;
http://www.hunterplastics.co.uk/download/29/Design Criteria.pdf

With an inspection cover so close, I would seriously consider installing a complete new stack on the outside corner of the wall & running underground to connect into the current chamber. Have a look inside the chamber, if it’s a reasonably modern plastic unit it will have additional capped off entry points you can connect straight into. The w/c can go straight through the wall above the floor & into the stack. The sink waste can then be a straight run under the floor between the joists out through the wall into the stack. The shower waste becomes more or less a straight run either on the outside wall or inside, boxed in below the ceiling. Depends if you’ve got any decorative pathways or anything else going on around the outside of the building; the cost difference won’t be a great deal & it won’t increase your fees as your going to need a Building notice anyway.