Dormer Construction: Rafters

It's New Year's Eve and today was even more annoying than yesterday. I thought the installation of the rafters (sloped roof beams) would be fast, but it ended up taking all day. The problem was again the geometry--both Jimmy and M. were getting confused by the slopes and installing the rafters at funny angles. Fortunately I noticed before it was too late--but by the time they got it right they had done it three times.

Getting started in the morning

Installing the 1st rafter

After the 1st redo

After the 2nd redo

Finally getting it right

End of the day

Dormer Construction: Framing the Slope

Today was rather annoying.

I had expected to completely finish framing the dormer and installing all the rafters today, but instead we only managed to frame the perimeter of the sloping roof. It turned out to be a lot trickier than any of us expected - part of this was due to  the geometry and the other part was due to the extremely poor shape of the hip rafter (the sloped corner beam) of the original roof . In preparation for doing the rafters, I removed the ridge tiles (triangular shaped tiles that protect the ridge/edge) and realized that we should reinforce this beam where we were building the dormer.

We then spent the rest of the day cutting intricate joints to get everything to fit together correctly...

Adjusting the final post

Installing the angled end beam

Positioning the other end beam

Looking good...but...

We soon realized the hip rafter was in bad shape and needed reinforcing

We added an extra piece of wood to reinforce the hip rafter. This was really tricky because it intersected many other beams at the top. These joints had to be cut by hand

Cutting away at the top, the beam to get everything to fit

The reinforcement

Finally - everything back together

Dormer Construction: Framing

After a much needed few days off for Christmas, we're back at it. Today we're starting to frame out the dormer and will be starting with the flat portion of the roof. The first goal is to set the main transverse beam (technically, a girder), which we soon realized would be best installed into the brick wall. Literally two minutes into opening the bricks, I got a call from our neighbor in the next building downstairs. Apparently the spot we broke into was her chimney and dust and debris came showering down. Fortunately she was cool about it, and we soon had it cleaned up and were back to work upstairs.

The girder (main beam) and the opening in the bricks to support it.

Closing up the opening

Once that first beam was set, we moved onto the other members that framed directly into the posts. In the process of doing this, we established the minor pitch of the "flat" roof (all roofs, even flat ones, have at least a slight angle to allow water to drain). After the perimeter was built, we filled it in with rafters that will eventually support the roof.

Attaching a perimeter joist (beam) to a post

Installing the "joist hangers" from which the other joists are hung

All the joists installed

Dormer Construction: Setting the Posts

Once we had the roof stripped, we immediately started setting the posts for the new dormer. These posts are the first part of building our dormer, and are anchored into the concrete ring beam. The plan is to set the posts, and then move on to the rafters (roof beams) that will frame out the small flat roof at the top of the dormer. A dormer is a vertical window that projects out from a sloping roof--our design call for a large dormer to give the new 2nd floor (loft level) a decent ceiling height. It has a rather funny shape due to the limitations of the historical district the property is in (the dormer is not meant to be seen from the street). This is why we have a very short post on one side--that part of the dormer will align with the main roof. Below is a 3D computer image of what it will look like when finished.

A page from the drawings - the proposed dormer viewed from the exterior.

The day started with M. (our day laborer) and I setting the steel base plates for the wood posts that Jimmy was finishing. Soon, we were able to start setting and leveling the posts and then moved onto framing the first horizontal beams for the flat portion of the dormer's roof.

Drilling the holes for the anchor plate bolts

A finished anchor plate

Jimmy finishing one of his columns

Setting the first column

Setting the first column

All columns set

Removing part of the roof truss

Lifting the first rafter (roof beam) into place

Setting the first rafter

Taking it all Off

It's Christmas Eve Day...and we're taking it all off!

Unlike the rest of the roof, we need to remove everything in this area : the slates, battens (small horizontal wood strips that support the slates) and even the rafters (the roof beams). The reason is that this will be replaced by the dormer and thus area will become our 2nd floor.

Dec 24th - morning. Taking down the temporary blue tarp.

Our temporary blue roof!

Open to the sky

11am - All the battens removed - only the rafters remaining

12:15 pm - all the rafters removed

All that we're keeping (for now) is the roof truss

There Goes the Roof!

From the moment we started looking at the flat, we knew the roof replacement would be the single biggest aspect of the entire project. With the structural work finally completed, it's time to start work on it.

I had originally planned on starting work on the front and finishing with the rear, where we would be building the new dormer. (A dormer is a vertical window that projects out from a sloping roof - our design uses a very large dormer to give the new 2nd floor (loft level) a decent ceiling height). Our Polish crew who did the structural works advised that we start at the back and build the dormer first, so it can help carry the weight of the new steel that will be installed along the roof's hip rafter (corner roof beam). After some thought, I realized they were right...so we're started at the back.

 

Morning of Dec 23rd - the original roof

As a result we decided to only demolished the rear face of the roof - the other sides would be removed once the dormer was completed. This would minimize the amount of the flat that was exposed and had no roof! The demolition started slowly - I first opened the areas where our posts would go - wanted to be sure it would be OK before ripping the whole thing off.

The first few slates removed - locating a post for the new dormer

 We also setup a string line to locate what would be the top of the new dormer. While allowing us to visualize what was to come, it also allowed Jimmy to start sizing the posts.

Starting at the top and working our way down. BTW - that's the living room down there!

Jimmy

4pm (it's gets dark really early in the winter)

5pm - wrapping up for the evening

At the end of the day we put up a blue tarp to protect the inside of the flat from any rain and moisture. Putting that thing up in the dark and wind was a total nightmare - have to find a better way to do that.

Loft Framing (Part 1)

With the steel ring beam  and primary steel beam both in place, we're now able to start framing the loft level, which will become the 2nd floor of the flat.

This new floor will be framed with wood beams that are inserted into these new steel beams for support, spanning between them. Installing this floor is necessary to begin work on the roof as it will provide a place for us to work from at the roof level.

We began by cutting all the wood beams to the correct size - for now we're just doing 7 beams and stopping where the opening for the new staircase will begin.

Cutting the 1st loft beam

A production line (of sorts) cutting all the beams

The cutting was straightforward, but once we started lifting the beams into place, it became apparent that they did not align correctly with the top of the steel beams which will be the level of the plywood sub-floor. To get them to align, we had to notch each beam so it would align properly.

The loft beams loosely in place (inserted into the steel ring beam)

Once enough beams were in place, we could loosely lay down plywood to walk on and from there were able to work a little easier, setting the remaining beams and then temporarily fixing the plywood so we could safely work on the roof...

Some loose plywood sitting on-top of the beams

A Steel Ring

With the concrete ring beam finished and the fabricated steel in the flat we're ready to install the steel ring beam. This is the last major piece of structural work in the project that before we start on the roof. Today we have everyone here: the Polish structural crew, the two Romanian day laborers, Jimmy and myself - 6 people in all.

The steel is first lifted into place by hand and then propped-up using wood posts into the final posistion. Once everything is correct, holes are drilled into the concrete beam and brick where an epoxy adhesive is used to anchor the bolts. As these things go, it's relatively straight forward except for the massive weight of the beams.

Dec 14th - Lifting the first piece

Setting one side into the steel beam

Propped up while one end is bolted in

Drilling holes into the concrete for the anchors

Waiting for the next piece

Dec 15 - cutting one of the pieces that did not fit correctly

Lifting the final piece

Tightening one of the splices and inserting the anchors

The completed ring beams