Bathroom in attic

[wookie6262]

I am thinking of converting my attic. Early days and I have a limited amount of money so I want to work with the features that are already there. I have nice deep 8 inch joists, so easy to run pipes etc. In the eaves, very close the the edge of the roof, there is internal cast waste and soil pipes. The access isn't great but I am doing the bathroom under them and have access at a lower level.

The first question is can you have a toilet running into the existing waste stack. The stack is in good working order but the top vents almost flush with the roof and I don't know if there is an issue with having so little height, about 500mm, to vent above the pan connector. Hope that makes sense.

The other issue would be ventilation. I would run a fan so presumably I would vent it through the roof. I would appreciate advice on what fitting would be required to get the 100mm pipe out through the roof and keep the roof watertight.

The rest is reasonably straight forward as hot and cold supply run down the pipe box with the soil stack and the combi boiler is close by in the attic.

Many thanks

 

[Slugbabydotcom]

Nice 8 inch joists in lofts can often be thin and not braced to prevent twisting. You may find you need to double them up to take the extra weight, especially if you plan on having a bath up there.
A soil stack should vent something like 900mm above the highest opening window or eaves and at any rate higher than the highest wc pan.
See 1.27 and 1.29 here for more detailed info.

I'm a little bit concerned about the pipes running in what might be a frost zone near the eaves. Don't be shy with the pipe insulation if the area goes outside the 'kingspan' zone

 

[Galoka]

The other issue would be ventilation. I would run a fan so presumably I would vent it through the roof. I would appreciate advice on what fitting would be required to get the 100mm pipe out through the roof and keep the roof watertight.

You use a weathering slate. eg:

http://www.screwfix.com/p/end-ventilation-slate-sp320/19121

 

[wookie6262]

The joists are 2.5" thick and feel very sturdy. The water tank that used to sit up in the attic was around 5'x4' and 3 foot deep. There must have been a couple of hundreds pounds of lead lining in it. From my untrained eye the joists are very strong and are solid as a rock. House was build in late 30s if that helps.

Interesting reading the regulations. I'm in Scotland so ours may be slightly different. However, as there won't be an opening to the building(presume this means a window) then I imagine it would be ok. I take the point about the stack being higher than the pan though. Looks like it is cut cast pipe and get the pipe above the pan connector to exit the roof higher up and clear the slates by a wee bit. I presume that bends in the portion above the pan connector won't be an issue. The attic is massive so plenty space.

All the water pipes are well lagged and the attic is only insulated on the floor between joists but not on the underside of the roof. I'll get a picture up tomorrow as it is quite difficult to explain.