Adding a bathroom - sistering joists, new water supply, new boiler + cylinder

[Mason-]

Hi all,

I'll try to be explain as briefly as possible. We want to add a bathroom upstairs where there wasn't one before. As well as moving the hot water cylinder up there. I had a structural engineer round to work things out. If we just want the bathroom, no strengthening is required. If we want the bathroom and the cylinder, we need to double up 2 of the joists.

This is a rough overview of the bathroom:


The engineers request:


The joists that sit on the wall to the left is easy, the top of that wall can be completely exposed so I can just sit the joist on top and bolt it to the existing. The issue comes with the right hand side, this is the party wall with my neighbour. Of course I need a party wall agreement.

Here is a photo of the 2 joists where they are socketed into the wall:



Here is where I need some help. I see these options:

1. Widen the pocket in the brickwork where the existing joists go to take both of the new joists. Messy but doable.
2. Some sort of hanger that I can fix to masonry. This seems impossible? The only one I think could work is a double width timber to masonry hanger. But to get it around both of them I need access from below, which I really want to avoid.

Is there any other option? Fixing a rim joist/wall plate and using a timber to timber hanger I don't think will be acceptable because it can only be in the space between the 2 joists which surely is not enough.

I appreciate any advice, thanks.

 

[Mason-]

Think I've found a suitable hanger

Welded Masonry Joist Hangers - A2 Stainless Steel

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That makes life easier.

 

[Mason-]

Random Q, why would they need to be connected to the existing joists rather than being in the middle of them and so just making the gaps smaller? Not sure if it makes a difference but that's why I'm no structural engineer!

Check load ratings on those things, not sure what the safety factor would be but they're approx 300kg each, share the load over the existing joists and it's probably fine?

I don’t know. Just going with what the man with the letters after his name says. The engineer has okay’d the hanger and what I plan to do. So that’s the plan.

Next issue is getting two 3.8m 2x7 joists upstairs… no way they’ll go up the stairs so I think I’m going to have to take a pane of glass out the window.

 

[Mason-]

Cheaper to get a new boiler instead of moving the tank at this rate

The boiler is going to be moved into the loft…. It’s a long long story. But basically my house is 1950s built. It has an original outbuilding attached to the back of the house. This is single skin single brick! A doorway has been knocked through internally to the outbuilding and it has: the only bathroom, the mains water goes in there, the boiler and cylinder are in there.

We want to knock it down and do a proper extension, but to do that I need to have in the main part of the house: a bathroom, and central heating. I’m also going to look at getting a new water main, because the current one I only get 9l/min which is crap.

 

[Mason-]

You've definitely gone OTT on this lol. I'd just sister them with some OSB screwed in!

I have to tell building control if I’m building a new bathroom where one didn’t exist before. And they’ll want an engineers report to say the floor can support one.

 

[Mason-]

Context if you care @dlockers and @Rob_B

My neighbours (mirrored semi detached), got planning permission 15 years ago for pretty much exactly what we want to do - they never built it though. The images below are from their application.

Here is the existing layout - you can see the single skin single brick part at the back has the mains water, and the boiler and cylinder as well as the only bathroom in the house.


This is what the planned layout will be:


Note this is my neighbours so it's mirrored, so the upstairs bathroom the tub is on the left in theirs but it's on the right in mine.
In that diagram I have already finished Bedroom 4 + 2. Bathroom is next, then Bedroom 3. Then save up to do the extension.

But the point is before that part at the back gets demolished I need in the main part of the house: a bathroom, a boiler + cylinder and mains water.

 

[Mason-]

Looks mega man. I didn't consider BC needed notifying about moving a bathroom (as you know I've moved mine from rear to front lol). I have also insulated more than 50% of the room but didn't bother, either. My span is ~2.2m though, not 3.7! So I can see why it was a valid question.

New layout looks brilliant.

From what I understand, if you're altering a bathroom where one already existed you're probably fine. But in my case there never was one so I have to get approval from BC. Even in your case, where you've moved it to a completely different location. Presumably all your first floor joists are the same size. So if they are strong enough to support a bathroom upstairs in one place, they should be strong enough to support a bathroom anywhere... but I'm not a structural engineer

It's a funny one with BC, it can only potentially be an issue when selling the house. And for that to happen the people buying the house have to notice that there has been a renovation and then ask a) "did they need to notify BC" and then if the answer is yes b) "did they?".

If they never ask the question then it's never an issue.

 

[Mason-]

the joist upgrade diagram just says screw/sister them not mentioning any additional end load support ??

what would be the practicality of installing the hanger, too - can you chisel out a slot at the required level, hopefully that aligns with the mortar, or, will you have to take out most of a brick and repack the gap.

That hanger I'm going to use, the flange lines up nicely with the existing mortar bed so should be fine.

 

[Mason-]

Bump. Did this all over the weekend. Exposed it all:



Cut all the wires going through the existing joists. Extended them all and temporarily put them ‘over’ the joists so I can sister the new ones:



Raked out mortar. Cleaned out the hole. Fit the joist hangers. Mortared them in. Splodged a load of CT1 on the back of them for good measure.



Sistered the joists as per the engineers directions. Added noggins in the centre.





Now it’s on to getting a new water supply. Current one is shared, 70 years old, and only get 9l/min.

Dug a big hole where I plan to bring it into the house. From this:



To this:




Going to be tricky here. Water pipe has to be 750mm below ground. Where it goes into the house it has to go in 4 inch waste pipe and the pipe has to be insulated.

My footing bricks only go 1 foot below ground level and then there are foundations.

I’m hoping I can core drill in the footing bricks. Then 45 down past the foundations. Down to 750mm and then 45 flat.

Water board guy is coming Wednesday so I’ll run it by him then.

Next step on the bathroom floor is to expose the right hand side. Put noggins all the way across. Then ply the floor. Then build the stud walls for the bathroom and new boiler room.

I’ll keep this thread up to date.

 

[Mason-]

Took the week off to break the back of this. Just a reminder of the layout I'm aiming for:

Exposed the other joists, added noggins all the way across, also made myself a little platform in the middle to work off with the cut floorboards.

First sheet of 18mm Marine Ply down. Screws every 100mm, seems like a lot, but when you think 6 inch floorboards had 2 fixings each, it's not actually that many.

All 3 sheets down:

Marking the layout of boiler cupboard and new bathroom entrance on the floor with tape:

And this is where I got to today before it was bedtime for the little boy:

Just needs a few noggins, and doubling up the studs where the door openings are.

Also need to cut an access hole in the ply for the gas/water/central heating flow + return, and new sockets for the boiler to go in, which will mean busting out the circular saw. I hate the thing, so loud, much prefer using a hand saw. I'm getting reasonably good at cutting square now, but I'm nowhere near a carpenter

It might not seem like much in a week, but what is not shown is all the noggins I had to put in the loft, and under the ply etc. Disconnecting the light switch to remove the old plate from the ceiling for the old wall. Removing one of the lights because the boiler room walls overlaps it, putting a plasterboard patch in etc. It's all the 'small things' that take time, I built all that studwork today in about 6 hours.Pain in the arse. I also got a massive splinter go up under my finger nail

 

[Mason-]

Nice work! Seems you're doing all the jobs I'd like to do in our place. Main bedroom is 4m x 4m and all suspended/full span. Quite bouncy, so I'd like to sister some joists or add noggings or both. Ideally I'd do it without fully taking up the floor though.

Does it feel much more solid now you've sistered up?

Thanks, yeah it's very solid, especially with the ply. I will overboard it with tileboard + flexible adhesive and try to level it. Then tiles on top.

I did blow some of the ground floor ceiling plasterboard screws, from whacking the noggins in place. Nothing too bad, tighten the screws, bit of filler and paint.

I am going to add some noggins between where the first 2 sheets of ply meet as well, as well as probably put some underneath where the bath will go, just for a bit more strength.

 

[Mason-]

You could take the new pipe in above ground if you want too, as I didn't want any hole below ground level as we have flooding issues.
All I did was drill a hole about 500mm above the DPC, use an approved plastic insulated cover and use an insulated conduit for the pipe near the house as it had to run close to the surface because of a culvert pipe in the garden.

Yeah there’s a product called a groundbreaker which can do that: https://groundbreaker.co.uk/products/groundbreaker/. I’m being really sad here… but I want the best flow possible, and they will add 2 elbows. I was hoping to run my pipe to the water softener/cylinder without a single elbow.

But I’m probably being silly, and one of these is probably the simplest solution.

 

[Mason-]

Sorry for the lack of updates.

Finished the Studwork:


Electrician fitted fused spur for boiler, fused spur for immersion, a double socket and a light to the boiler cupboard.


Fitted Rockwool Sound Slab to the stud walls and plaster boarded it all.



New megaflo eco slimline 200i in place. Box has Vaillant ecoTEC 620. It’s going to be snug! Also gonna have a water softener on the floor in there.


Time to core drill into the kitchen for new water supply. Measured off of the window… measured 3 times. Put my pilot drill through.


Far too close to the copper pipes!!! Drilling level would have a been a good idea… d’oh!



Went with it anyway… yolo.

Great success.



Regs say if the water pipe is not 750 below ground it has to be in 4 inch duct and insulated.



Fitting the insuDUCT is gonna be a challenge. 40mm waste is coming from washing machine. As well the gas pipe is in the way…. Have to fix 5 things to move forward 1 step…



And finally had my first go at soldering. Made the diverter section for the water softener. Can’t test if it’s water tight yet. But pretty happy with it.





See you in a few weeks

 

[Mason-]

Looks good --- did the sparky just runt he fused spur from the ring? Asking because my plumber did basically the same when he relocated to the loft. I wasn't sure if it deserved it's own circuit...

Can't remember the exact words he used but it is advisable or preferred, but importantly not mandatory, to have it on its own circuit - it's not really feasible in my case to run a new circuit from the consumer unit (without ripping up recently renovated rooms flooring). So it's just off of the upstairs sockets, which is fine really what other high powered stuff are we going to have upstairs, at most probably a hair dryer. The immersion is a backup as well, it should be being heated by the boiler all the time unless there is a fault with the boiler. The electric power draw of the boiler is negligible.

Did you have to buy/hire core drill bit(s), or more powerful drill - had the water board confirmed increased flow rate if you had your own pipe ?
( still need to dig into it - I live on a hill flows not brilliant for upstairs combi shower but think I'd really need a pump
anglia water measured static pressure 2.2Bar/22mh , total 40ltrs 10mh apparently )

The pipework for the bathroom bath tub will all be above floor I guess to avoid compromising new joists.

My brother had a set which I borrowed, when he stopped working for British Gas he was going to start his own company going private so bought some core bits. But he didn't bother doing it in the end, works on national infrastructure gas pipes now.

I just used my Titan SDS, have to say I'm impressed with the clutch, a few times the bit caught (probably something to do with my pilot hole being sloping down!!!) and the clutch was perfect, my wrists and arms are fine.

They haven't advised on flow, said estimated pressure is 3.5-3.8 bar. Considering my current supply is shared, and I don't know what size it is underground but I do know it comes into my house in 15mm copper. By going to 32mm MDPE there should be a big improvement in flow.

 

[Mason-]

Sorted the first obstacle for the INSUduct today. Getting the 40mm washing machine waste running across to the existing gully out of the way. Had to add a new gully and chop out some of the clay pipe to put some plastic fittings in.

Grinding the clay pipe out was a pain as there wasn’t enough space to get the grinder around it all. So had to cut chunks out bit by bit and then tidy up the ends when the middle section was out.



There was quite a lot of water in the pipe itself. I guess the fall isn’t so great.

Next mistake was after I was halfway home from tool station I realised I didn’t buy any lubricant for the pipes. “It’ll be fine” I thought, that was a mistake.



Biggest issue was the adjustable bend where it went into the tee. The middle part moved fine but it wasn’t rotating in the tee at all so couldn’t get it where I wanted. Tried some fairy liquid on all the joints and then everything moved nicely and I could manipulate it all the way I wanted.

Relieved that’s done. Just need to get the gas pipe moved by someone gas safe registered then I can chop a bit of the weather bead off, and fit the INSUduct.