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.

 

[Mason-]

Nice work. No first fix plumbing under the floors before they went down?

With the way it’s gonna be laid out. They’ll all be in false walls.

I am gonna lift some of the ply again though…. To put some sound insulation in.

 

[Mason-]

Sorry for the lack of updates. Anyway… before I had moved the washing machine waste out of the way. Next thing to move out of the way was the gas pipe.

The lower part is going to the existing boiler. The upper part is going to the new one. It’s just capped under the floorboards for now.


After that I was clear to fit the insuduct. I grinded some of the render off so it would sit relatively flat.

Fit the back half and the elbow. Had to notch the insulation out to make the elbow fit in nicely.

Above 75cm the pipe has to run in waste pipe and be insulated.

So it’s 2 135s to get it over the foundations, and then in to a large swept 90.



Then had to get this pipe through….


Was a massive pain in the arse. 32mm MDPE is so rigid. Lots of swearing later…



Connected up


And done…


On to the inside. - should have left myself more pipe. Was a pain in the arse but from this:



To this:







Now got to wait for the Moling company and the water company. So on to the inside now. Working on the boiler room and bathroom.

 

[Mason-]

Moling company came on Friday. And moled from my boundary to where it goes into the house. About 20m or so. And also as I have a 1m retaining wall. Means digging a trench would have been a nightmare. Would need a 1.75m hole on the other side of the retaining wall.

So they dug on the street side and moled from there.




They did a great job. He was very complimentary of my work. Asked me if I was a plumber lol. Probably just buttering me up.

Just need affinity water to connect up to the main now.

Anyway, on to the internals.

The plan:


The reality:



First time doing some proper soldering. Fairly happy with it. Can’t test it though until the water company connects up.

For the outside tap: because the cupboard is small. Aiming to drill from the outside in, I didn’t want to risk it. So my plan was to drill an 8mm pilot hole from inside to outside, hoping for minimal breakout with an 8mm bit. Then use my 22mm bit from the outside in.

Well that plan went to ****, look at the blowout from the 8mm bit…



Anyway, drilled it out with 22mm and put 22mm copper pipe through as a sleeve for the 15mm water carrying pipe.

Patched up the render:



Will paint it tomorrow and hopefully fit the outside tap.

 

[Mason-]

Hi, sorry for such a long time between updates. Any of you with young children will know it's hard to find time. I work a standard 9-5, by the time I get home, it's dinner time, bath time and bed time. And I can't really work on the house when my little one is asleep. So it's more or less weekends only, and then the time I do spend working on the house I feel guilty for not spending it with my family. So it's been really tough.

Where we were last time I was a couple of weeks away from my new water supply being fitted. Long story short, the council wouldn't grant the roadworks permission as of proximity to a school, so we had to wait until the next half term. Which was mid February.

Prepare yourself there's gonna be a lot of photos.

In the meantime I did some work inside:

Fitted some architrave and a door to the boiler cupboard



I knew after I did the bathroom flooring that I forgot something, didn't put any insulation... d'oh! The lounge is underneath and I want to reduce noise as much as possible. So I put in 100mm of Rockwool Sound Slab.




After that I started on the pipework to the boiler cupboard:

Flow on the left (next upright is the return), u bends in the joist gap to the right and goes into a little manifold, directly up to an aav. First drop down is hot water flow, next is bypass flow, and last is central heating flow. Gas pipe not run as I am not gas safe, will need someone registered to do that.


Here are the valves, two motorized valves and a bypass valve

Soldered up the bypass straight to the return

Felted up to stop creaks and rubbing


Here you can see what will be the main hot water coming off the cylinder, it travels down, goes into the wall to feed the new bathroom (alongside balanced cold supply). Then drops into the floor to feed the rest of the house.


Cylinder in


Boiler on the wall (just temporarily to show what it'll look like (it's cramped! but didn't want the bathroom being any smaller)


Flow to hot water cylinder done, had a double bend on that with an elbow.


Return from the cylinder just freshly soldered , can also see some of the water pipework too (mains water is coming into here, then being softened, feeding the cylinder, then going back out to the rest of the house)


Pressure reducing valve (3 bar for megaflo cylinders) + Isolation valve for the softened cold supply. This will isolate the entire soft cold water to all of the house when it's all plumbed in.


So the 2 vertical pipes are. On the right is the softened water coming in straight from the softener. It then has an iso and a pressure reducing valve. It comes down, tees off to supply the bathroom, tees off to supply the cylinder (and drain off + iso), and then you can't see it well but it goes down into the floor to supply the rest of the house with soft cold balanced pressured water.
!!! I made a mistake here !!! didn't fit the Pressure Relief Valve for the cold supply in, so that will be rectified.


Just another snap of it all:


The water now. The pipe coming up on the right is cold mains in, it tees off in 15mm which will be the filling loop for the boiler. Then it goes up to a standard 'bypass' setup for a water softener.


Here is what it'll be like with the softener in situ:


Not sure why I took this photo. The 2 pipes closest to you are the flow and return out to the central heating system.
The two below in blue clips. The one that cuts across the joists is the balanced soft cold supply going out to the rest of the house. The other one is the water straight from the softener going to that big vertical pipe.


Here is what it looks like outside of the boiler room
You can see mains in, soft cold out, and soft hot out from cylinder.

The two 22mm pipes in the next joist space along with the plastic push fit caps on are the existing flow and return to the C/H system. so will connect on to that when the boiler is up and running.
As well you can see the mess of pipes that used to supply a sink in a bedroom and a toilet.


Removed the unnecessary pipework and now you can see things a bit better. Everything is right next to the existing pipework, so when I do 'the big switch over' it's all very close together.


Now the water supply has finally arrived!!!
I snuck out and hopped over the fenced off road works and had a peak... not often you get to see a water main and a tapping ferrule.
There's the old 4 inch supply in the road and my new connection in 32mm MDPE



I was bricking it turning the supply on as it was the first time my soldering would be put under pressure, all the soldering you've seen so far, none of it has been tested . Luckily none of my soldered joints leaked, a few compression joints leaked but after tightening them, it was leak free. Success.

The only thing plumbed up to test the new supply was the outside tap. Turned it on and it absolutely blasted out!!! for about 5 seconds then reduced to a trickle. Rather confused, I realised there was probably some crap in the pipework being flushed out, and as it goes through a non-return valve to get to the outside tap, it might have blocked it.
Alas, I was right, can you see that little stone in there


Got quite a bit of grit out.

Afterwards, it blasted out again. Tested the new supply vs old by filling a 2l coke bottle. Old supply managed 10.5l/min, new one manages 21l/min. Great success!

Getting the NRV out, and fitting it back in was really hard, I had to cut the pipe. So had to reconnect it all and solder in a patch


Next was sorting out connecting the mains to the kitchen sink, which meant taking the dishwasher out and a lot of fiddly soldering. Also took the cupboard off the wall to see if the boxing in of the existing supplies to the kitchen were accessible... they weren't.



We're up to the present now becuase this is work I did yesterday. Took the cupboard back off the wall and opened up the boxing to see the pipes.


The plan is to do this:


And the reason why is because that boxing comes up in a 5-6cm gap between the joist and the external wall and it is a nightmare. The existing plumbing is a joke! And very hard to make neat. Sorry for some reason I didn't take a good before photo (this is just in the background of another photo) but here you can see where the pipework comes up through the floor and how much of a state it is.


ANyway, removed the old 15mm copper that dropped in supply mains (from the old supply) to the sink, so all that is there now is the soft water to the dishwasher, and hot water to sink


Next was cutting this hole to get the mains upstairs. It was an absolute pig, no room to get anything in there, as well there are live pipes behind so I had to be very careful. In the end I stitch drilled 6mm holes on my impact driver beacuse a drill won't fit in there, and then knocked the hole out with a hammer. Lots of swearing!


Dry fit 22mm mains going up:



Soldered in:


Removed all of that mess in that lo-res image, and ran 15mm


Here you can kind of see the finished product.
The 22mm with the plastic cap, is the new mains cold I just ran up. Next to it is the gas supply for the boiler (the other bit of capped 22mm is redundant and I will move it later. And the 2 15mm pipes are the soft cold + hot supplies. You can see in this photo that gap between the joist and the wall on the right, that's where the pipes came up before.... Wish I took a better before photo.



Dry fit:



Barely visible with the cupboard on. I did have to cut into the boxing lower than I hoped though... So some patching up to do.




There is still a lot more to do for the bathroom. But most of the fiddly stuff is done... Hooray! If you made it this far, thanks for reading.

As well one thing you may have noticed in the boiler cupboard is none of the waste pipes are done.

Temperature and pressure relief valve from cylinder + boiler need a way out, condensate from boiler needs a way out, the water softener drain and overflow need a way out. As well I need a hole for the boiler flue, as well as the gas pipe. All of this now I will get a gas safe engineer to do.