Bathroom:Waterproofing the floor

The final push to finish the bathroom waterproofing has come down to today, which is a Sunday - my flight back to NYC is late tomorrow afternoon, so anything I need to do has to get done by the end of the day today.

 This will include affixing the waterproof tile backer boards (Marmox boards) to the walls and floor that will be tiled (outside of the shower). These are the final bits of waterproofing, and this will allow our tiler (Sean) to complete his work. Since I'm leaving tomorrow and he's still going, it's become apparent that his work will (unfortunately) only be finished after I've gone. This makes the perfectionist/architect in me nervous, but I've seen over the past week that Sean is very meticulous and we've spent a lot of time going over all the details and issues...so hopefully it will be OK. But "Aglaya" is going to have to step up and take charge after tomorrow!

Marmox boards lining the bathroom walls

Once the waterproofing on the bathroom walls had dried for 24 hours, I was able to apply the waterproof tile backer boards (Marmox boards) Sunday afternoon. Similar to the shower, after the boards are fixed to the waterproofed plywood, the joints are sealed with a waterproof silicone bead, followed by waterproof tape.

After removing the loo

After the walls were completed, it was time to focus on the floor - I had been nervous about this, as it involved removing our loo (toilet) in order to fully waterproof the floor below. Fortunately it went relatively smoothly and was easy to remove (with a little help from "Aglaya").

The plywood under the loo waterproofed, and the 1st batch of flexible tile adhesive ready to go

With the loo out of the way, I quickly applied the waterproof membrane to the plywood and after it was dry enough (could not wait the 24 hours this time!), I prepped for putting the Marmox boards on the floor. This involved pre-cutting all the boards so they would fit, and then mixing smaller buckets of the tile adhesive.

The first batch of the flexible tile adhesive spread out on the floor

It's worth pointing out here that I had ordered a special type of tile adhesive for the floors. Wood joists with a plywood sub-floor are not the best base for tile because they have a tendency to subtly move due to expansions/contractions in the heat/cold. In an old Victorian building like ours, movement could even be caused by large truck driving by outseide. These very small  movements have a tendency to make tiles -- or the grout lines between them -- crack, so one has to minimize the possibility of movement, while still accommodating for some movement. Here I had fixed the plywood with as many screws as possible to make the subfloor as rigid as it could be, and will then apply a flexible tile adhesive that is designed to go over wood subfloors. The adhesive will fasten the Marmox boards to the floor (minimizing the transfer of any vibrations or movement) while the Marmox board itself will provide a very rigid and inflexible base for the tile. The hope is that this carefully thought out system will minimize any cracking of our large, beautiful limestone tiles...

The 1st Marmox board in place on the floor - using some sacks to hold down the boards in a few areas

Yours truly placing the 2nd Marmox board in place

Spreading the next batch of adhesive

A close-up view of the adhesive - one uses a notched trowel so the adhesive grabs the boards better

Mixing smaller amount of the adhesive made it easier to work with, and within two hours I had all of the Marmox boards in place. Similar to the walls, beads of silicone are placed bewteen the joints, and then taped over with a waterproof tape.

The silicone between the joints (on the left); the silicone covered by waterproof tape (on the right)

After the work is completed, the loo is fixed back in place

By the end of the day (10pm!) the bathroom floors and walls were completed, and ready for the tiler to carry on with his work in the morning...

Building the Bathroom: Enclosing the Walls

I’m finally back! It’s been almost 2.5 months – the longest I’ve been away from London and the flat for quite some time. I’m gearing up for a busy couple of weeks, because we’re on a tight schedule – “Aglaya” booked a tiler to start work in the bathroom on February 20th, so I have exactly 7 days to finish all of the build-out, waterproofing and prep work before he can start. We had originally thought about just tiling the shower for now, but we soon realized that 4/5 of the work (and the cost) would be the shower. At that point we realized that it made sense to give it just a little more time and money and simply get the whole room done as part of our Big Push. It’s going to be tight – there’s a lot work to be done, but I think 5 days should be enough…

In December, I had completed most of the shower’s build-out and installed most of the Marmox tile backer board on the walls. What remained was completing the shower’s base, and building out the ledge and walls of the bathroom (outside the shower), which will be soon covered in limestone tiles. The only work done on these surrounding walls (so far) was the basic stud framing, so they would have to be covered in plywood, waterproofing and Marmox backer board. For the ledge, it would have to be framed out, and then covered in the plywood, waterproofing, etc.

February 13 - the exposed wall studs

The most exciting part of this will be closing up our temporary door, removing the blue tarp and building out the real door we will eventually be using every day. The real door will be on the opposite side of the room from where the current, temporary one is. In the final layout, the bathroom will be en-suite, accessed from the bedroom.

Before starting - looking the other way towards the temporary door (shower on the left)

I started by laying out the ledge – the idea here is that it wraps almost completely around the bathroom and into the shower, so we can put thing on it while providing a place to transition from stone to mirror. I framed out the ledge using short studs fastened to the full-height wall studs. This ledge also had to hide the cistern of our new toilet, so had to take it into consideration with the dimensions and layout.

Using a string line to framed-out the ledge & keep the studs aligned

End of the day - ready for plywood in the morning

Once the studs were in, I used a string line to find the level and started attaching sheets of waterproof/boil-proof plywood (WPBP) that would act as the substrate for the waterproofing and tile backer boards. The plywood also helps tie everything together structurally, while minimizing any movement that might cause the tile or grout to crack in the future. In doing this, the larger the piece of plywood, the better job it does tying everything together, so this required some rather intricate cutting.

Morning of Feb 14th - first piece of plywood

Second piece had lots of intricate cuts

Installing the second piece behind the toilet

Lower part of the wall/ledge completed

Once the long wall (where the toilet is located) was finished, I moved on to the shorter wall (where the sink will eventually go). This is where our temporary door is located, so for the time being I’ll finish everything but a narrow opening. If we weren’t living on site while doing the work, I wouldn’t have to worry about this (and just close up the temporary door now), but I’d prefer to minimize having to going in and out through “The Box” – particularly once the tiler starts his work which can be quite messy. So in the meantime, we have this workaround…

Feb 15th - Adding plywood along the other wall and around our temporary door

Montage of the bathroom fully enclosed with plywood...except for our temporary door!

Sourcing Tiles

The bathroom construction has gotten far enough along that it's time to pick out and order tiles! This is a huge step for us, psychologically - if we're starting to select finishes, then it means we're finally beginning to see the light at the end of this long, dark tunnel of construction.

We have actually managed to accumulate almost four dozen stone samples! But (as with everything else related to this project!) it was a bit of a journey to get to this point...

The piles of stone tile samples

We had initially looked at tile over a year and a half ago, back when we were optimistic that construction would be relatively quick and painless, and before things got complicated. At that time, we had visited several tile shops in and around London, collected around a dozen samples and had picked out a few options we liked: dark(ish) porcelain tiles from Spain. But as the bathroom construction progressed, and after actually living in the flat for many months, I started having doubts about those porcelain tiles: they now felt too dark, and too "perfect". Considering how much character the ceiling now has and our intention to re-use the old wood floor planks, I had a gut feeling that we should go with a natural stone that was lighter in color.

Two types of slate from a supply shop in Vauxhall: a honed wine colored (left) and a riven-cut "oyster" ( right)

A type of limestone they called "Barcelona", but that was not readily available.

That meant starting the search for tiles from scratch. At least (having spent time doing it a year and a half ago), I already knew of a few good places - but I had forgotten how far away and how spread out across the city these shops were. As a result, I ended spending close to a week running around London collecting samples and determining availability.

Just outside the shop in Vauxhall - you can see the "Shard" under construction. Designed by Renzo Piano, soon to be the tallest building in Europe when completed

The showroom of a shop that specializes in stone tile - located on the edge of Southwark & Southfields

A showroom wall with different types of stone

A marble installation

Eventually we started to realize that "Aglaya" really wanted a colorful and varied stone, while I was gravitating towards a cleaner, simpler limestone. I had envisioned the bathroom as having two different stones: one for the shower area and another for the rest of bathroom. Because I was extremely taken by a warm toned limestone (with a hint of blue) called Batieg Azul (which came from Portugal and Spain) we started focusing our efforts on finding a second stone that would be more colorful but would also complement this limestone.

The Bateig Azul installed in a showroom mock-up

A detail of the Bateig Azul limestone

We soon decided that slate should be our second stone. I knew that there were hundreds of types of slate - in my New York office, we have several drawers full of slate samples from a specialty supplier there, but for some reason I could only find a few options in London. Eventually I found a specialty supplier of slate in Finchley (north London) with several dozen options, including a copper colored slate that "Aglaya" absolutely loved.

Once we returned to the flat, we were pleasantly surprised to see that the copper slate really worked well against the limestone. We slept on it for a few days, tried other options, but the combination of copper slate and Bateig Azul remained our favorite.

The honed Copper Slate on top of the Bateig Azul

We decided not order the stone before I return to New York, but "Aglaya" can place the order a week before I return to London again...

Heating Up: The String Never Lies

Today my goal was to start hanging the new layer of plasterboard over the old walls. The reason for this (as you can tell from the pictures!) is that the existing walls are old, nasty and horribly wonky. Not only are they wonky, but they are covered in white wallpaper...apparently in the 1970's, there was a fad here in London to "paper" walls rather than paint them. It makes no sense to me, but I've heard from friends who tried to peel it off (when doing their own DIY renovations) that it was a miserable and difficult thing to do. Having had our share of drama on this project, I thought it best to avoid that...

The existing, old walls

In speaking with builders and our building control officer, I had learned about a technique called dry-lining.This technique hangs new sheets of plasterboard onto old uneven walls using dabs of plaster adhesive. When done properly, these dabs hold the new boards far enough off the old walls that you can create a straight, flat surface without being hassled by the old surface...a perfect solution!

Looking down the wall

In researching how to do this, it became apparent that one of the most critical aspects would be to locate the line of the new surface and make sure it will be straight and level. This may sound easy, but it's not - particularly in an old building where nothing is straight. You basically have to find the point on the old wall that sticks out the furthest, and then set a string line from that.

Holding a straight edge to one of the old walls - the light coming through shows how uneven it is

In doing this, one of the first things that became apparent was how wavy the old walls were...in all directions. Not only did the surface bow along the vertical, but it also moved in and out along its length.

Checking the vertical level of the wall (you can see the wall bowing away here)

I soon realized that the string line was actually too accurate! Because of an imperceptible shift in the old wall, it turned out we would lose almost 3 inches to achieve a perfectly straight surface. It may not sound like much, but in a small space...everything counts! So I ended up taking off my "architect hat", putting on my "builder hat" and "cheating" a bit by adding my own shift to the line so as to retain those precious inches. The shift was hidden along the edge of a window so it would be imperceptible to even the sharpest eye.

Because all of this took so long to work I ended up not hanging any boards today, but at least with the string line set, I can start first thing tomorrow.

Setting the string line - the new plaster boards will stop at that line.

Powering Up!

The first task on our heating list is to provide power for the boiler. Since this requires having our trusty electrician onsite, it makes sense to have him do the initial work to rewire the flat at the same time. This will require us to relocate and replace our old breaker box (also known as a distribution panel or a circuit breaker panel) with a new one - not only to meet the current building regulations, but because the old one is super sketchy! The breaker box is where the power comes into the flat and is then distributed to all the various areas - that's why it's a big job to replace and relocate it - there's a ton of cables going to and from it.

The existing breaker box (in the orange bag) with the jumble of wires going to/from it

The day started by meeting up with our electrician and going shopping. We ended up spending half the day getting all the electrical materials in Park Royal - an industrial area in northwest London with many supply houses. We went from shop to shop ordering the various components and comparing prices because we could not believe how expensive the cabling was - particularly the very heavy lines that were needed to carry power to the breaker box.

Eventually we made it back to flat - while I was rushing to frame the wall where the new breaker box will go, the electricians were removing the sub-floors, disconnecting the old power lines (after shutting off the power!), and running new the cables.

Disconnecting the old breaker box

The new heavy duty cables to relocate the breaker box - so much color!

Removing all the old cables & connecting the new ones

The new breaker box installed in the wall framing

Almost done rewiring the main lines

The old breaker box

The actual work at the flat went very quickly - we probably spent more time picking up the materials than rewiring the flat. In the end, the final result was a subtle red line that indicated the boiler had power. I had not realized the old wiring & breaker box was in such a poor state, but I now appreciate how much safer the flat has become - the new wiring and breaker box now meet the current building regulations which are very, very tough.  Without seeing firsthand the differences between the old and the new, it would have been hard to truly understand and appreciate.

The boiler with power (on the left); and the jumble of old wires gone

That's one "Hot Deck" you have there...

I'll be returning to London tomorrow to start working on the next phase of the roof construction, which is the insulation & waterproofing. I thought it might be helpful to briefly describe what kind of roof we're going to do and what it's made of:

The type of roof we're decided to do is known as a "hot deck", which means that the insulation is located on top of the "deck", which in our case is the wood planks. Normally, the insulation is located underneath the deck, in between the rafters - here that's called a "cold deck". The disadvantage of the cold deck is that one can get condensation on the interior, and there may also be issues of pipes freezing. With a hot deck, all the insulation is on the exterior, so it minimizes any water or condensation inside. A "hot deck" also allows the underside of the wood planks (our deck) to be visible--which is a key aspect of the design.

So here's the composition of our "hot deck" roof: 

1. Directly on top of the wood planks is a heavy black plastic sheet known here as a "damp-proof course". While actually watertight, it is intended to prevent the accumulation and seepage of any condensation as a result of the insulation.
2. Above the black plastic is our rigid insulation which is required by the new building regulation to reduce the amount of heat and energy needed in homes. We're required to achieve a very high level of insulation, so it works out to be 120mm (4 inches). These sheets are large (4ft x 8ft) but fortunately don't weigh much and can be easily cut.
3. Above the insulation we have our primary waterproof membrane known as the "breathable membrane" As it's name suggests, it's breathable, which helps to prevent mold within the roof cavity. As far as I know this is not really used in the US, so I'm interested to see how it works.
   
4. The breathable membrane is held down by wooden battens which are narrow strips of treated wood. The battens are fastened to the rafters using a special helical nail that's 200mm long (8 inches) and designed specifically for hot roofs. These batten are installed vertically to allow any water to flow down the slope towards the gutter - with a vertical orientation, they become known as "counter-battens".
5. Above the vertical "counter-battens" are the horizontal battens which the slates are nailed to. These battens must be perfectly straight and precisely installed otherwise the slates will go awry.
6. Finally, we have the actual slates which are the traditional method of roofing here. The slates themselves are totally watertight and supposedly have a 200-300 year life expectancy (the modern membranes typically last about 20-30 years).
   

Staining Planks

It's Sunday and we're staining planks. Because we're expecting to install several hundred planks this week, we need to stain as many as we can. The planks are raw pine, basically a light tan color, so to get them to match the darkened, 120 year old rafters, we need to stain them dark.

Staining Planks

Fortunately "Aglaya" is helping me with this, so we were able to do something together and she was able to get more "hand-on". It's was cold, but otherwise a nice time to have a chat and catch-up on things while working together

Flying Steel

With the concrete ring beam completed, we're now ready to install the steel ring beam. There's a lot of debate among the guys that this steel ring beam is overkill. It seems that on any construction site--either in NYC or here in London--the workers love to complain about the engineers over-designing everything. I partially agree with them, but as this will become our home, of course I think that it's better for it to be slightly over-engineered than not.

So the structural design calls for the concrete beam (which stiffens and consolidates the top of the brick wall), and then bolted to that is the steel ring beam, which provides additional lateral stiffening to prevent the roof from kicking out the walls. The way the building was originally built, the wooden ceiling joists did this job--but we have now removed all of them! These pieces of steel are much larger and heavier than the 3 sections of our beam. These are "c" shapes known as channels and because they are cut to 4 meter (12ft) and 3 meter (9ft) lengths they are extremely heavy.

I flew in last night, and first thing this morning went to meet one of our Polish structural crew to go rent an electric hoist. Our plan is to attach that to the top of the scaffold and then hoist it up the outside of the building and then into the flat.

The steel delivery

Takes three guys to lift one piece

Tying the 1st beam to the rope and hoist

Here goes the 1st one...

Up and away!

When the steel is properly balanced it only takes one guy to guide it

We staged a guy on each level of the scaffold to guide the pieces as they go up.

Jimmy is in front of the window

One of the smaller 3 meter pieces through the window.