Floor Leveling: Day 2

Today we started leveling in earnest. First thing in the morning, we completed removing floor boards and then started setting the string lines. This was quite tedious as one has to establish the high point and then set a string over each joist relative to that point. It took us a while to get it correct, but once we had it, we were able to start cutting the strips of wood used to level each joist.

In the morning - realizing how much work is ahead of us

Setting the string levels

The water level hanging from a string

Cutting one of the leveling strips

An installed wood strip between the joist and the string

A series of leveled joists

Bedroom ready for plywood

Fastening the plywood to the leveled joists in the bedroom area

Floor Leveling: Day 1 - Demolition

Today we started the process of leveling the floors. As in many old buildings, the existing floors are slightly wavy, so when doing this degree of renovations it's usually a good idea to make the floors level. Because the original floor boards appear to have a lot of character, we're hoping to re-use them. That's going to cause more work, as we'll have to carefully remove them, take out all the nails, and then at the very end of the project, put the boards back down and refinish them. But re-using the boards will allow us to save wood and should hopefully retain some of the character of the old boards.

The process of leveling the floors begins with clearing the floor of everything, then removing the old boards one by one. Once the boards are removed, the floor joists will be exposed and we'll be able to establish the level using strings and a small water-level. (The danger of open joists is that one must be careful to walk only on the joists otherwise you could risk putting a foot through the neighbor's ceiling!) The string over each floor joist shows the distance that it's off from level, so that distance is filled with a strip of wood. Each piece has to be custom cut, so it's a slow and tedious process. Once all of the strips are in, we can start fastening sheets of plywood down for a sub-floor. That sub-floor is safe to walk on and ultimately will have the finish floor boards nailed to it. Here, I'd like to ultimately install a 2nd layer of plywood but put a roll of sound absorptive material to help minimize the noise transmission from the floor.

Clearing and cleaning the floor of everything

Removing the old carpet sub-floor boards to expose the original wood floors

The original floor boards

Montage of flat with original floor boards exposed

The guys: Jimmy, M, and yours truly (from left to right)

The first few floor boards out

One can now see the rafters - and the neighbors' ceiling

Moving In

The most momentous day, I think, since we completed the purchase: today, we moved into our new home!

I guess my hope that it would only be a few days after moving out of the rental flat was radically wishful thinking, because it's been 3 weeks since we've been itinerant. And in truth, even now we've moved onto a construction site rather than moving into what most people would consider an actual home.

What will become the living room

To get it to the point of livability, we had to ensure that the roof was totally closed up (so we wouldn't get rained on while inside!). There isn't a functioning boiler, though (that means no heat and no hot water!), and this is one of the coldest winters London has seen in years (just our luck...) You can see your breath inside!

So, we also had to build a little enclosure in which to hibernate. We sealed off the space that will eventually become the bedroom, creating temporary walls out of plywood. We're calling it "the Box"--and it will basically be our home for the immediate future since the rest of the flat is still strewn with pieces of insulation, plywood, power tools, and every other type of construction material imaginable. And did I mention it's freezing! Since "the Box" is relatively small, though, it shouldn't be a problem to heat it with fan heaters. And we bought an air mattress. A roof over our heads, something to sleep on... what else does one need?

Loft Framing (Part 2)

In anticipation of moving-in tomorrow, we're trying to finish framing the loft floor so we'll have a ceiling above the temporary bedroom. Because of everything that's going on (patching brickwork and  waterproofing the roof ) we were only able to start this work in the early evening, which mean that we had to rush before it got too late.

Jan 25th - the partially framed loft and original structural stud wall

To complete framing the loft, we have to add new joists that are perpendicular to the original loft joists we set last month - these new joists have to change directions in order to accommodate an opening in the floor for a staircase that will eventually come up-to the loft. 

To accommodate this change in direction, these new joists will hang off of a double beam (on one end) and will sit on a structural stud wall at the other end.  Before setting these new joists, the top of the structural wall has to be shortened to the correct height, and a new wall plate (horizontal member) has to be set. This wall plate is what the new joists will sit on.

Trimming the top of the structural wall

Once the new wall plate was set, we also set a new full length beam that will act as the edge of the loft/floor. After this beam was in place, we were finally able to hang the smaller floor joists  using steel brackets.

Setting the first few floor joists on the structural wall

The next morning - a partially framed floor

Adding the remaining joists

By the end of the day we were  able to start fixing the plywood sub-floor...proving a ceiling to the temporary bedroom. While we were not able to completely finish the plywood sub-floor, it will be enough to get-by...at least for now....

Checking everything is lined-up before starting the plywood sub-floor

Fixing the plywood sub-floor to the joists

Our New Ceiling!

After all the work so far - we're finally starting to see the result of our efforts. It's Sunday and we can't work, so I spent some time soaking in the ceiling...

(These are the planks that we spent several weekends staining earlier.)

Montage view from the corner of the Living Room

View ceiling over living room

View from loft level (2nd floor) showing steel reinforced hip beam with replaced rafters and new wood planks

Detail showing steel reinforced hip beam with replaced rafters and new wood planks

Montage View of the entire flat

Roof Insulation & Waterproofing - Day 2

Today we continued installing the insulation on the roof and pressed ahead with the waterproofing.

As previously mentioned, the insulation is covered by a waterproof membrane that is breathable. This breathable membrane is required by the UK building regulations, but it's actually really great. Once it's on, the roof essentially become waterproof and can stay that way for several months before the slates get put on. The membrane is held by wooden battens which will ultimately be used to nail the slates in place.

The goal today was to install some more insulation, but to also put down the first few rolls of breathable membrane. This would also require us to fasten the first few battens using a special helical nail that is 200mm long (8 inches). This special nail should save us a considerable amount of time as it fastens the entire roof assembly (battens, waterproof membrane, 120mm insulation, and the damp-proof course) directly to the rafters with one nail. I had originally bought many wood studs to hold the insulation down, which would have taken considerable time to cut and install. Now we can use this wood to do other things.

The trick with these helical nails is they have to go into the rafters below. This is much harder than it sounds because we have 7 inches of insulation, planks and plastic hiding the exact location of the rafters. The way around this is to mark the rafters locations with pencil onto the top layer every so often, before covering everything up.

I was nervous to see if all of this would work and save time...

Bringing a new piece of insulation up

Insulation cut and placed into position on the side roof slope

View from the top

Transferring the location of the rafters so we could see where the battens go

The first two rows of the waterproof breathable membrane

The first two battens being attached with the special 200mm helical nail

Starting to come together

Looks like it's all working!

Towards the end of the day - most of the batten are fixed

Roof Insulation & Waterproofing - Day 1

Today I returned to London after a quick trip to NYC, and the plan is to start installing the insulation and waterproofing.

As you may recall from a previous post, I went back to NYC just as we had finished the structural work on the roof and were finishing the installation of the planks. While the roof is now structurally sound, it's not watertight, so it's been covered with tarps in the meantime.

Temporary tarps to keep the water out

Today we're going to start installing the insulation and the two layers of waterproof membrane. These waterproof membranes will keep the building watertight before the slates go on, but once the slates are installed, the membranes act as back-ups for the slate in case any water makes its way in. (I've described our "Hot Deck" roofing system in detail in yesterday's post, so if you want to understand it in detail please take a look at that post.)

View from the top - cleaning the roof & removing the temporary tarps

Cleaning the planks and roof before starting the insulation

The first few pieces of insulation on top of the "damp-proof" course (black plastic)

Cutting one of the first pieces of insulation

Trimming the edge of a corner piece

Laying the black plastic "damp-proof course" back into place

End of the day - the black plastic and insulation

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).
   

Roof Construction: Open Heart Surgery - Day 4

If all goes well this will be the last day of our open heart surgery on the roof. It better be - I have a flight at 8:10pm back to NYC - but if there's a major problem I can't leave with the roof half open.

Because we ran into trouble last night aligning the rafters on the side roof slope, we have to start the day with re-aligning them. The plan is to use a string line and a long, straight 2x4 to make sure they are properly aligned (wish we had done that last night!). Once that's done, our day laborers will start installing planks while Jimmy and I move onto attaching the rafters (hopefully straight) on the front roof slope. If all goes well we will have all the rafters re-attached and aligned and all the planks installed before i leave for the airport...

Re-aligning the rafters on the side roof slope

Rafters attached to the steel reinforced hip beam

Starting to attach the wood planks on the side roof slope

Montage of open roof from the living room

Re-fastening the first few rafters on the front roof slope

New planks on the side roof slope (left) - re-attached rafters on the front roof slope (right)

Loose rafters on the front roof slope

Rafter ends - they hook over a 3"x3" horizontal wood stud called a wall plate

Planks halfway up the side roof slope

Attaching the final rafters

Rafters finished - planks almost done on one side...

I had to run to the airport without getting exactly to the point that i wanted - but we were close enough that it was OK. The rafters are completely finished, and the guys were finishing the planks on the side roof slope as I was leaving. They will continue with the planking tomorrow and Friday until it's done - everything will then have to wait a few weeks until I get back from NYC...