Move waste pipe for free standing bath

[Alex Edge]

Hi All,
Hope to get some advice.
Fitting new bathroom with free standing bath so need to move feed and waste. I’ve a problem with the soil pipe as it’s current location from the top will be too high when putting back floor. Ideally I need to come off the bend so as to give myself more height. Does such a fitting exist?
Thanks,
Alex.

 

[Riley]

So you are looking for all the waste to be under the floorboards

 

[Burger]

Hard to tell from photo, but are you not able to use a 90 degree bend or spigot bend off the up stand of pipe? I doubt you would get a fitting if one exists onto that soil bend as access is tight.

 

[Steve weightman]

If i get what you mean then a stem elbow off the adaptor should get you moved elsewhere

 

[Alex Edge]

Hi,
thanks for suggestions and ideas.
Riley: yes need waste pipe to go under the floor.
CBW1982: can't take anything from the top as there isn't enough height / gap. Can't get access to the down pipe. See additional photo.
Steve: yes I was hoping I could get something off the elbow as it's lower and accessible- is this designed for use on an elbow or general pipe fixing?

 

[Riley]

So are you taking waste through joists?? I wouldn’t

 

[Alex Edge]

So are you taking waste through joists?? I wouldn’t

I'd prefer not but don't have another option. Would do my best to add additional support where I could.

 

[Ben-gee]

There’s always another option.

What’s below? Might be better to run between joists to edge of room and drop down through ceiling and take it from there..
If it’s utility, no problem.
Kitchen, bring out above wall cupboards won’t be seen etc etc

 

[Alex Edge]

There’s always another option.

What’s below? Might be better to run between joists to edge of room and drop down through ceiling and take it from there..
If it’s utility, no problem.
Kitchen, bring out above wall cupboards won’t be seen etc etc

Good idea but unfortunately I can't as bathroom is in middle of the house. Directly below is the middle of the kitchen so no cupboards close by. The only way I can add a connection with enough space below the floor is on the elbow bend. Anywhere else is too close to joist or floor. I've considered bringing the waste pipe up and boxing in around the edge but this would probably end in divorce...

 

[Alex Edge]

Additional photo showing restricted height.

 

[Riley]

There is no 90° Radius adapter.

 

[Alex Edge]

There is no 90° Radius adapter.

damn!

 

[Brambles]

Whilst no one can stop you cutting through a joist, it is difficult to do so for a 40mm waste pipe and comply with Building Regulations. Bear in mind that in a bathroom, the imposed loading on the floor is one of the highest in the property - for a full bath around 350kg over 4 or 5 point loads. So weakening a joist under a bath is not the best of ideas. The joist will probably not fail, but the potential for the floor to flex will increase, as will the risk of cracking in the decoration below.

A built in beam ( which yours are not) are more forgiving to cuts in the lower centre section - however, Building Regulations would still mot a allow a hole to suit a 40mm waste in joists of the depth you have.

Your beams are simple (rather than built in)
joists on hangers. If you have time, lift the flooring for the length of the joist, then drop in ( on steel plate hangers) a second joist in parallel - but offset by 3 to 4 inches.

That allows you to cut through the first beam into the side entry spiggot, without compromising the strength of the floor.

Ideally you prepare the new beam, but make the cuts and pipework connection through the existing beam, just before you drop in the second beam - you have better access that way.

Cutting and strengthening a plate hung timber joist is quite difficult. The area at risk is the bottom section which is in tension - so this normally requires a second short beam or steel plate to be bolted onto and through either side of the beam before you cut through - you don’t seem to have the space to do this.

Hope this helps

 

[Alex Edge]

Whilst no one can stop you cutting through a joist, it is difficult to do so for a 40mm waste pipe and comply with Building Regulations. Bear in mind that in a bathroom, the imposed loading on the floor is one of the highest in the property - for a full bath around 350kg over 4 or 5 point loads. So weakening a joist under a bath is not the best of ideas. The joist will probably not fail, but the potential for the floor to flex will increase, as will the risk of cracking in the decoration below.

A built in beam ( which yours are not) are more forgiving to cuts in the lower centre section - however, Building Regulations would still mot a allow a hole to suit a 40mm waste in joists of the depth you have.

Your beams are simple (rather than built in)
joists on hangers. If you have time, lift the flooring for the length of the joist, then drop in ( on steel plate hangers) a second joist in parallel - but offset by 3 to 4 inches.

That allows you to cut through the first beam into the side entry spiggot, without compromising the strength of the floor.

Ideally you prepare the new beam, but make the cuts and pipework connection through the existing beam, just before you drop in the second beam - you have better access that way.

Cutting and strengthening a plate hung timber joist is quite difficult. The area at risk is the bottom section which is in tension - so this normally requires a second short beam or steel plate to be bolted onto and through either side of the beam before you cut through - you don’t seem to have the space to do this.

Hope this helps

Thanks for the detailed explanation. I will look into this further. My initial thoughts are it would be made more difficult by the pipes, but these things are never easy! Typically how far apart are the joists that are 90deg to the joist we are talking about?

 

[Brambles]

It depends on the depth if the joist and the span - generally you want a spacing that keeps the deflection below 1 in 360 to avoid cracking the ceiling.

I cannot tell sizes from your pictures, but I would say a 400mm joists between centres would suffice.

Obviously you have got to remove the pipes - but you are only weakening the original joist so drop in a joist that is 25mm less in depth align it with the bottom of the original joist - then reinstate the pipes in the same location.

The flooring does not need to be fixed to the additional joist - it is there purely to prevent the original joist failing in tension on the lower edge.

At the end of the day, it all comes down to how important is it for you to have a concealed waste pipe.

I guess, that with reasonable DIY skills you are looking at a weekends work, taking it gently.

When putting in new joists, measure, measure, measure - then cut, check the measurement and instal!!

 

[Riley]

Remember you are also looking to get fall on the pipe so it’s going to just get more and more difficult. I would be more tempted to redesign your layout and use something like this Traditional Luxury Exposed Bath Drainage Kit | Victorian Plumbing
Don’t buy it from here because they are terrible but I’m sure you get the idea

 

[Alex Edge]

It depends on the depth if the joist and the span - generally you want a spacing that keeps the deflection below 1 in 360 to avoid cracking the ceiling.

I cannot tell sizes from your pictures, but I would say a 400mm joists between centres would suffice.

Obviously you have got to remove the pipes - but you are only weakening the original joist so drop in a joist that is 25mm less in depth align it with the bottom of the original joist - then reinstate the pipes in the same location.

The flooring does not need to be fixed to the additional joist - it is there purely to prevent the original joist failing in tension on the lower edge.

At the end of the day, it all comes down to how important is it for you to have a concealed waste pipe.

I guess, that with reasonable DIY skills you are looking at a weekends work, taking it gently.

When putting in new joists, measure, measure, measure - then cut, check the measurement and instal!!

Thanks Brambles good advice.

 

[Alex Edge]

Remember you are also looking to get fall on the pipe so it’s going to just get more and more difficult. I would be more tempted to redesign your layout and use something like this Traditional Luxury Exposed Bath Drainage Kit | Victorian Plumbing
Don’t buy it from here because they are terrible but I’m sure you get the idea

Thanks Riley that is a completely different way to look at the problem. I will give this some serious thought tonight and discuss (argue) with the wife.

 

[Riley]

Ultimately you WILL have some pipe on show so you could work with what you have

 

[Ben-gee]

Riley’s solution has the other big advantage of being able to monitor and address any future issues should they occur - what you spend on the fancy waste you’ll save on timber/bolts/plates etc and a lot of time.

 

[Ben-gee]

Other way is to box in pipes, obviously, but less obvious is to make this boxing oversize in height - giving your missus somewhere to rest her champagne flute and expensive potions . Ie tile it and make feature.

 

[Burger]

Is there no way of removing the upstand pipe and rubber bung, renew the bung and come off on a spigot elbow?

 

[Rob Foster]

Dont cut the joists under a fancy big bath, its nuts,
1m3 of fresh water weighs 1 tonne, unless you fancy it joining you downstairs
centralheatking

 

[Luke Richmond]

If drilling through joists
drill hole in line with boss adaptor drill through Joist then straight through into boss straight and connect in with new boss on the side rather the top outlet and just blank current one off

 

[Riley]

That will make the hole in the joist even bigger I’d not