Building a Staircase: Design

The next stage of the project is to build the staircase that will lead up to our new 2nd floor (the loft). The loft was framed out over a two periods: just before we started the roof and just before we moved in; it sits over the bedroom, bathroom and kitchen.

Cut-away view from digital 3D model (used during design phase) showing how the new staircase leads up-to 2nd floor loft

Developed during our design phase back in the summer of 2010 (!), the staircase will consist of 3 parts:

• The first flight of stairs starts at the edge of the bedroom door (where the floor was extended) and runs up to a landing . This will be an "open riser" stair, meaning the vertical elements of the stair (known as risers) are gone. Because the stair sits over the entrance to our terrace (with glass doors), we did not want to block the light, so not having a risers will allow light to pass through the staircase.
• The second part is the landing, which is bolted into the exterior brick wall (just above the door to the terrace).
• The final part is the 2nd flight of stairs, which is turned 90 degrees and starts at the edge of the landing and goes up to the loft. Because everything is so tight, this second flight will pass through the bedroom after passing through the structural wall opening that was framed out yesterday.

While the design intent was established long ago, I only developed the actual detailed design of how it will be built over the last few weeks. These drawings were initially done by hand - once they were finished, I submitted them to Building Control (the London version of NYC's Building Department). After a few minor revisions, Building Control approved the design for structural integrity and deemed it compliance with the UK Building Regulations (similar to NYC's "Building Code").

3D hand sketch showing the structural elements of the staircase

This approved design details how the landing becomes a structural element that will be bolted into the brick wall on one side and fastened to the structural stud wall on the other. Because the first flight of the stair has no risers,  each tread (the horizontal "step") is notched into a large 2"x8" structural stringer (the diagonal element) on each side. This will make the flight incredibly strong while still allowing light to pass through. This flight is then attached to the landing using heavy screws and steel plates.

Section sketch showing the primary stringer and steel plate that assists in the connection to the landing.

One of the design ideas that made the stair more difficult to build was the idea of keeping the 1st flight a few inches away from the wall. The idea is to allow light to pass through this gap - both from the terrace door, but also from a light cove that will eventually built above (in the ceiling at the edge of the 2nd floor) - allowing the light to pass through should not only provide additional lighting for the stair, but should also create a great looking effect as the light washes down the wall.

From a structural perspective this mean that this 1st flight could only be held at the top and bottom, not also on the sides, as with most stairs. Because the landing is itself partially cantilevered, this meant that only through the combination of both landing and stair would the entire assembly actually be strong enough. This was achieved by allowing the primary stringer to be attached to the side of the landing using an additional piece of 2"x8" wood (creating a heavy angled "L" shape) that's stiffened by a heavy steel plate at the joint. This angled "L" shape will act almost like a column to hold the hanging end of the landing - this can best be seen in the section sketch (above) and plan sketch (below).

While everything looks good on paper, we'll soon see how it well it works in reality...

Plan view of landing and how 1st flight of stairs is fastened to it.

Rebuiding "The Box"

With the structural wall re-framed and the floor extended, the entry and walls to the bedroom are mostly framed out and we're almost ready to have the plasterboard (called Sheetrock in the US) replace the temporary plywood walls. It's because of these plywood walls that we call the bedroom "the Box" - since we moved in, the "bedroom" has been enclosed by plywood, making it look like a "box". But today...that's going to change!

The re-framed structural wall and extended floor in-front of "the Box"

The first thing that needs to be done is some additional minor re-framing of the structural wall (also one of the bedroom walls) to create an opening where the new staircase will pass as it goes upto the loft (2nd floor). This work was left until today because in order to do it, I'll need to remove all the plywood. Taking down the plywood was technically easy to do, but psychologically, this is a very big deal for us - we've been living with it for over a year, and this is the first step to returning to some level of normalcy.

Temporary plywood walls of "the Box" (photo on the left) - a few minutes later, the first few panels removed (on the right)

All the temporary plywood removed from the re-framed structural wall along the bedroom

With the plywood removed, I was able to easily cut out the opening and set a new wall-plate that will act as a structural anchor for the new staircase. This completed all the re-framing work and I could now begin re-sheathing the walls.

Cutting out studs to make an opening for the staircase

The completed opening

 The re-sheathing of the bedroom began with adding plywood - but this time it's permanently attached to the exterior face of the structural wall. This plywood is being required by our official from Building Control (the equivalent of the Department of Buildings in NYC) to make the wall extra strong and stiff so that it acts as what's known structurally as a diaphragm system. The entire wall is sheathed in structural plywood and fastened every few inches with screws. Later, this will be covered with plasterboard and painted - eventually it will be blended in and hidden.

The first piece of structural plywood added

A few more pieces of plywood seen from inside the bedroom. The opening for the staircase is on the right side

The completed plywood seen from outside the bedroom - the door opening is again visible.

Once the plywood was completed, I shifted my attention to the other walls so as to hang the plasterboard. Before any plasterboard could be hung, the wall that separates the kitchen from the bedroom needed to have the final studs installed. These were quickly cut, placed and leveled.

The remaining studs installed at the side bedroom wall

Once the studs were in place, it was finally time to start hanging the plasterboard. I hung one board on the side wall just to see how everything fit together, and then quickly insulated the structural wall before covering it with plasterboard. All the walls will be insulated to help with sound dampening and to retain heat within the bedroom during the winter.

The first piece of plasterboard in the bedroom!

Insulating the structural wall.

Hanging plasterboard is quite not as basic as it sounds. Building control requires us to maintain a 1 hour fire rating around the bedroom, which can be achieved with either 2 layers of regular 12.5mm (5/8") plasterboard or one layer of special fire-rated plasterboard - which in the UK is, funnily, colored pink (to make it obvious the board is rated). Here I decided to use the pink (rated) plasterboard along the structural wall (because it won't have much traffic/abuse) but two layers of regular board on all the other walls (so they are stronger and can take more abuse & traffic).

A few more boards up - the pink (fire-rated) plasterboard on the front wall with regular board on the side wall.

Most of the plasterboard hung

The plasterboard went up rather quickly - but by this point it was late, and I was getting tired after a 12-hour day of labor. But the plasterboard made a huge difference in how the room felt - the plywood is gone, and our bedroom is finally starting to feel like a real room rather than a plywood box!

End of the day - the bedroom re-sheathed in plasterboard

Structural Wall Surgery

While the extending the floor, I was somewhat simultaneously re-framing the only remaining Victorian-era structural wall left in our flat so as to accommodate an opening for the new bedroom door. This door location is only possible because of the floor extension - the new door is squeezed in between the top of the old staircase, the kitchen and the beginning of the new staircase that goes up to the loft.

Perspective from 3D computer model used in the design phase - the new bedroom door and new staircase (upto new loft) meet at this critical location adjacent to the new kitchen

This arrangement was developed in the design phase when it became apparent that in order to open-up the space, yet maximize the size of the kitchen and bathroom, we would have a very tight convergence at this very location. This convergence makes the floor extension and relocation of the door critical to the new layout. At the time it was not obvious this wall was structural (it supports a post that helps hold part of the roof) but having worked previously on this wall, and reviewing the proposed work with building control, I felt confident moving forward.

March 27th - The original Victorian-era structural wall (plaster was removed during demolition)

The "surgery" involved cutting through the existing studs to create an opening that will fit the future door. As in all structural work of this kind, the most important thing is to brace the areas of the wall that are doing the structural work so that the wall does not "know" that you're re-arranging it - it's almost like a magic trick. If the structure realizes what you're doing...you're in trouble...

So the first step is to brace the beam at the top of the wall (known as a wall plate) that is actually carrying the weight of the roof post above it (that helps support the roof). The brace is rather simple - a heavy stud (old growth wood from the original roof) that sits on top of temporary beams that span the opening in the floor for the stair.

The temporary brace to support the wall-plate while structural work occurs

Once the brace was in place, I began to cut away at the studs and re-frame the wall to accommodate the opening. Because this wall is one of the bedroom walls, I did this work keeping the plywood sheathing in place, since the plywood acts as the temporary walls to the bedroom, keeping the dust out. But this made the work more difficult, so I had to go "old-school" and use a handsaw...

Cutting and removing the first pieces of the wall

Using a handsaw at a tight spot where power tools would not fit

The opening is done and new side studs repositioned...all that's left is horizontal member at the top of the door opening

Once all the members that were in the way were removed, I was able to reposition the vertical studs (doubling them up on one side for more strength) and then finally add a double "header" at the top of the door opening. A header is the horizontal member at the top of a door - because this wall happens to be structural, this header is structural and will do the primary work of transferring the weight, or "load", of the roof post to the rest of the wall.That's why the header is doubled up and additional vertical members are added using steel clips to ensure their position and strength.

Once everything was in place, I held my breath and removed the temporary brace...all is good!

The brace is removed and the newly re-framed door opening is complete

Before & After montage. On the left (before): the structural wall and floor - On the right (after): the extended floor with the new door opening

Extending the floor

After almost a month in New York, I'm back in London again. Now that the shower is finished (!), I'm going to shift my efforts towards finishing the remaining "heavy construction" so that we can try to wrap up the major work by the of the summer.

What that means is that I'll now be focusing on the preparations for the new staircase that will eventually go upto our new loft & dormer. This will include:

• Extending the floor so it meets the correct location of the new stair. Besides adding around 15 sq ft to the overall area of our flat, this extension will also provide the necessary floor area to locate the new door into the bedroom (currently, "The box"). So this extension is critical to the new layout & design of the flat.
• Re-framing the structural wall (adjacent to the staircase) so that the new door into the bedroom can be opened.
• Once the structural wall is re-framed, it needs to be sheathed in structural plywood and then covered in "fire-proof" plasterboard (1hr rated to be precise), as per the instructions from our council's Building Control officer.
• Build and install the landing for the new staircase - it needs to be built first because it will help hold up the stairs...also, it will give the stairs something to frame into
• If the above items go well...start building the staircase...!

The existing staircase (down to the flat's entry door), with the structural wood wall next to it

Before extending the floor, I needed to open up the existing floor and determine the exact location and level of the new beam that will carry the new floor area as well as the new staircase. Because this is the only remaining area of the floor that was not leveled, the contrast (between the old sloping floor by the stair and the new leveled sub-floor) became quite obvious...with a difference of over an inch!

Morning of March 26th - the existing conditions and original end of the floor.

Sub-floor removed, exposing the joists underneath

The level shows the extreme difference between the old sloping floor/joists and where it should be so it's level.

Because of the extreme slope of the old floor, I realized that it will be necessary to reconfigure the top of the stair to get everything level. This required pulling off the top step so as to fully expose the beam below. Once the joist was fully exposed, I was able to set-up a string line and determine the future leveled location of the new beam.

Removing the original top step to expose the beam below

The string line and level - note the difference between the string (which is level) and the slope of the old floor/beam!

The location on the structural wood wall were the new joist will go. Removing the plaster to expose the wall plate below where the beam will sit. (A wall plate is a horizontal stud within a wall - usually in between floors)

With the location of the beam determined, it was time to create the openings for it to go into and determine the structural support that will hold it. On the side of the exterior wall, I cut into the wood trim and exposed a wooden wall plate that holds the joists (the wall plate sits on top of the brick wall below). On the other side (at the structural wood wall) I also found a wooden wall plate that was conveniently at almost the exact location I needed to sit the new beam on. Once everything was opened, I cut the new wood beam and inserted it in place. It took some time to set it at the exact level, but I was eventually able to get there.

Afternoon of March 28th - locating the wall plate that will hold the new beam (at the exterior wall) and establishing the correct level there. This required a thin steel plate to get it to the exact height needed.

The new beam at the correct level (notice the difference between it and the old beam)

Once the beam was set to the correct level, a second beam was cut and they were fastened together (this is known as sistering) to create an extra strong beam. This double beam was then fastened to the old, sloping beam to help stabilize it and prevent any further settlement or sloping.

The double beam fastened in place

Now the fun part started...I was able to remove the old railing and start setting up for the actual floor extension. This again required using string lines to determine the correct location of the new joists (that will frame into the double beam). Once everything was worked out, I was able to to cut the wood and install special steel clips (called joist hangers) that help make the structural connection between the joists.

Morning of March 29th - The new double beam in place...then removing the original railing.

String lines locate the positions of the new joists.

With everything cut and the joist hangers in place, I was then able to insert the new joists and fasten everything together. Within a few hours they were structurally sound, and i was able to add a layer of plywood so we could walk on our new extended floor!

The joist hangers in place, holding the new joists

The completed framing

Adding a piece of plywood so we can walk on it...

Another major milestone!

After two long weeks, I bid farewell to our tiler, Sean, on March 2nd. In the end, tiling our irregularly-shaped shower was complicated enough that the job took him fully twice as long as he had anticipated. I certainly didn't mind, though - he did a fabulous job and I'm very pleased indeed with the results! Here's a link to Sean's website:  http://www.tile-with-style.co.uk/

You may be surprised to learn that it was only today, almost a month later, that we reached the major milestone of being able to run our new shower for the first time. It turned out that (as usual!) there was a complication... this time, it was the fact that our limestone tiles turned out to be extremely porous indeed. Sean applied 2 coats of sealant, as promised, but even then, he explained, the tiles weren't fully sealed. This meant that they weren't fully impervious to water, and so he strongly recommended that we didn't run the shower until we had applied enough coats of sealant to make the tiles fully water-resistent. Thus began my journey into the world of tile porosity and sealant types...

It took me about a week to research different types of sealant to find out what, if anything, would be compatible with the sealant Sean had already applied; in the end, I decided to just get the same stuff he had used, although I had to order that online. I also had to learn how to tell when the job would be done, so I would know when to stop sealing. It's actually fairly straightforward: if water forms little beads when you splash some on the tile, you know it's sitting on the surface and not being absorbed.

But by the time I had gotten to the stage where the sealant had been delivered, the applicator purchased, and the knowledge gained, I was off on a week's holiday to see my parents. And I knew André would be back just five days after I returned to London myself, so naturally I decided that he'd do a better job sealing the limestone than I would!

André sealing the Limestone

But finally, 25 days after the tiling was completed, we reveled in our ability to run our new shower in our beautifully tiled new bathroom. A HUGE milestone!! And a long-awaited one... as the last big milestone we hit was turning on the heat, back in October. All that remains to be done in the bathroom now is to build the ceiling, add the vanity and sink, hang the mirrors and install the glass shower door... but in the meantime, at least we can now use the shower!

The tiled shower!

The shower floor

Montage of the tiled bathroom - eventually there will be mirrors over the plywood walls

Colours!!

I was a bit nervous about the tiling job being finished without André around to oversee things - we've spent an enormous amount of time and effort on this bathroom, and André is a total perfectionist! But it seems to be going well so far. I'm at work during the day, so coming home Tuesday and Wednesday evenings and seeing the gradual transformation of the bathroom as Sean (our tiler) nears the finish line is quite an experience.

The bathroom floor nearing completion

My major contribution has involved colours. Now, if you think about colours in the context of a home-building/renovation project, you'd most likely think of something fun, like choosing paint or tile colours. I had to spend hours yesterday colour-matching – but I was working with grout!

With all the tiling finally finished, Sean now needs to seal the tiles, apply grout, and then seal them again. Grout, for those who are not familiar with it (and I wasn't, at all, until 24 hours ago!) is the stuff that goes in between tiles that seals the joints and makes them waterproof. Normal, bog-standard grout is white, but André had decided that we needed to match the grout colour to our tiles so that it would look right. I hadn't even known that grout came in different colours, but even I could see that white grout would look terrible with the tiles we're having installed.

Grout samples: colors straight out of the bag

For the limestone, it was easy. We bought Mapei Ultracolour grout in "medium grey", and saw straight away that it was going to be a good match. The slate, though, proved to be highly problematic. We bought a bag of a colour called "terra sienna" but found that it was too light, and too orange-y. We thought that Mapei's "brown" would be perfect – but we couldn't find it anywhere in London. Apparently because brown grout is not a product that people ask for very often, none of the suppliers we checked with had it in stock, and we'd have to order many bags in order for them to do a special order. In any case, we'd need about a week for it to arrive if we went the special-order route - and Sean was planning to do the grouting today, Thursday. The next closest colour was "chocolate brown", but that turned out to be too dark.

Early mixed sample...too orange-y

I thought that under the circumstances we'd just use the grey for the slate as well (Sean's suggestion), since the overall colour scheme would work. But André was determined to get everything to match (that perfectionist thing again...!). So, I got up early and spent an hour before going to work yesterday mixing up little test batches of grout (you just mix the powder with water), combining the different colours in various proportions to try and get something that would match the slate! I'm no colour theorist, so it wasn't easy – plus, I'm not a morning person…

Another sample...getting closer, but this one is too dark

I applied the various test batches to several tile offcuts, left them to dry, and went to work. But when I got home in the evening, I discovered that none of them really matched perfectly. I took pictures of the samples and emailed them to André, who was not pleased *at all* with the results. So, I spent the rest of the night - actually, until 1.30am! - doing more colour combinations and test batches. Finally, *finally*, I figured out that the magic combination was 25% "terra sienna", 25% grey and 50% brown.

The "Magic" Combination!

This morning I got up early again, as Sean (who I suspect thought we were a little crazy for taking this much trouble over grout - he said he'd never seen anyone do such a thing!) did not want to be liable for mixing the colour himself. (He did the first coat of sealant yesterday, so today he was ready to start grouting.) So before he started his work for the day, I mixed up a big batch up the magic colour and left him to it...

Mixing the final batch of grout