How can we avoid raising wet room base when there is limited space for the fall on the waste pipe?

[Very_worried]

We have a shower base for a new wet room which has a lip around the hole for the waste. The lip lies about 1&1/2 inch below the level of the base. But this is a problem as we are already at the minimum cross fall on the waste pipe, which means raising the base up by an inch to maintain the cross fall. But we don't really want to raise the floor level in the wet room. Is it possible to get a vertical outlet / shower waste, connect it to a U bend, and run it back up to the waste, snug against the wet room base to avoid losing an inch off the floor?

The other thoughts we have are to cut the whole lip out and seal a larger waste to the base, but not sure how difficult this is?

Or, I guess, buy a different wet room/ shower base? Ebay seems to have bases without a lip, but are they strong enough to be used without support underneath (i.e. directly on to the joists)?

Thanks a lot for any thoughts / comments

 

[HootingOwl]

So you are doing a DIY wetroom on a timber joisted floor. I salute your bravery. A picture would help...

 

[Very_worried]

Yes, it's a challenge. Photos here - do they make it any clearer?

Thanks a lot for any suggestions.

 

[stardanny]

Where do the waste go to? Soil stack or outside gully?

With a wooden joists floor, can't you lower the waste pipe down?

Daniel.

 

[Very_worried]

The waste drains into a soil stack, but the run is long – over 3m. Hence I need a reasonable drop over that length. I’m at the limit of how low I can go in terms of the exit of the pipe into the soil stack, so no unfortunately I don't think I can just lower the waste pipe down a bit.

 

[HootingOwl]

if you cut/grind the lip off the tray you will ruin the tray and probably cause it to leak/crack etc

3m isn't far to go. A fall beween 1 in 40 to 1 in 60 is what you need so 5cm is needed. Use 50mm pipe if you are worried about discharge rate.

 

[Steelmasons]

You could purchase an extension piece in order to raise the trap outlet , not knowing the type of waste/trap fitting/s then it's anyone's guess.
Maybe call a plumber??

 

[Very_worried]

You could purchase an extension piece in order to raise the trap outlet , not knowing the type of waste/trap fitting/s then it's anyone's guess.
Maybe call a plumber??

I'm sure calling a plumber is not a bad idea, and yes it may even come to that .

I've not seen such extension pieces; any idea where I might look for one online?

 

[Steelmasons]

Post a picture of waste outlet.

 

[Very_worried]

if you cut/grind the lip off the tray you will ruin the tray and probably cause it to leak/crack etc

3m isn't far to go. A fall beween 1 in 40 to 1 in 60 is what you need so 5cm is needed. Use 50mm pipe if you are worried about discharge rate.

Yes, cutting it off didn't seem like a great idea really . So you're saying it will be ok even if the gradient is very shallow? We can manage to find 5cm I think!

 

[Steelmasons]

I've not seen such extension pieces

I guess you wouldn't have..

 

[HootingOwl]

18mm in every 1m is considered optimal for a vented stack so a touch over 5cm is the target. You could probably stretch it a bit more if using 50mm waste pipe.

 

[HootingOwl]

Online? Locate a decent independent plumbers merchant in your area and visit them at a non-busy time. Most are very helpful. The national chains are hit and miss when it comes to counter staff.

 

[dilalio]

Use 2" and make sure you put a rodding eye at the end of the run with a T out the wall instead of an elbow - then, if your pushing the limits of the fall, you've always got a "get out of jail free" card.
What depth are the joists?

 

[Very_worried]

Post a picture of waste outlet.

Here is the shower outlet; I thought it was a pretty standard design but what would I know?
Thanks for any advice, though I think I'll try the independent plumbers merchant - after just double checking if we can achieve the 18mm per m