Building Blox: Week 7 – Ground floor taking shape

What we did:

  • Brickwork to ground floor ceiling
  • Steelwork installed
  • Timber joists installed to form first floor

Many of us are used to working in environments where details are key; everyone is expected to read up and cross-check.

In the fast-moving environment of construction, where experience and pragmatism is often instead king, some of these (technical) details within the specification can get lost, potentially with consequences. Much of your choice in choosing a contractor will lie in how much faith you have that their experience will deliver in these instances. This week I had to trust that mine knew what he was doing when going against the specified design.

When designing a building,...

…a structural engineer must provide technical details for major parts of the build, such as the foundation depth, wall make-up and steelwork. This is all based on unique attributes such as ground conditions, building design and loads. In a standard residential build, most should be quite standard, but some special considerations may need to be made.

A consequence of my design having large windows and doors to the front mean the section of wall separating them is quite narrow. This means there isn’t as much support on either side, so a lateral force may cause some displacement. These forces would most commonly be from wind, but also from earthquakes as is shown in the image below.

Lateral forces (Courtesy: LA Times)

As I’ve quickly learnt, common/traditional construction in the UK relies largely on compression, so any lateral movement would be catastrophic! Thankfully this isn’t so common, so we’ve all been ok.

To get around the issue of this section of wall, the engineer specified ‘wind-posts’ which provide more lateral restraint – these tie a vertical line of blockwork to a solid base, using long posts fixed to the ground floor.

Wind posts

The issue for me is that the contractor didn’t think this was necessary so ignored the detail, creating a conflict with the engineer, so I had to call a meeting to have it out resolve this…

A stroke of luck

Turns out we could do without the wind-posts, saving time and effort retrofitting them. The saving grace was that within my design, the WC internal wall is perpendicular to this short section, so as long as these are adequately tied together, there is enough lateral restraint to avoid needing the wind-posts. Of course I had no foresight of this when designing the building, so I can say we got lucky! Issue averted.

Even if I hadn’t (accidentally!) designed this, the case for not including the wind-posts was strong, so the contractor had further built up my faith in him.

"One problem at a time"

Rounding up the engineer and contractor meant we could also cover off some other points on the roof design, which as it currently lacks some details, may create some tension in the coming weeks. But as my contractor likes to say, he’d rather tackle one problem at a time, so we can revisit that…

On Easter Monday I found a massive hole dug up on the public road by the main entrance to the site. This wasn’t an egg hunt gone too far, but National Grid’s search for a gas leak, making it more difficult for large vehicles to enter the site. Fortunately, most of the materials required were already on site, so this wasn’t too much of an issue, but still led to a few curses around the site.

Ground floor taking shape

By mid-week the brickies had built up to ceiling height, installing lintels above windows and doors. These metal frames bridge the gap between openings, so brickwork can continue above them. It seemed like everyone onsite preferred to call them lentils, but after making the same joke a couple of times that those wouldn’t make great building materials, I stopped correcting them..! You can see one installed below.

Lintels installed

Lintels installed

After reaching ceiling height, the steel joists could be positioned and the timber joists installed to make up the first floor. To do this we got in a new and what seemed like unnecessarily big forklift. Bigger is usually cooler here though!

IMG_6188

Unnecessarily large forklift

To make up the first floor, long timber planks are set at approx 400mm intervals between the steel and blockwork and are tied together using small ‘noggings’ – more here. (If the name isn’t strange enough, apparently in Scotland these are called ‘dwangs’!) This is all then tied into the building using blockwork and steel straps for added stability. You can see me getting a little lesson below!

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Lesson on joists

By this point we could clearly see the ground floor space which was amazing. The first floor going on was also a nice milestone, so a great week of progress!

Next week we plan to get the scaffolding in to start the ‘second lift’, laying block/brickwork at first floor level. Hard to believe we’ve come this far in 7 weeks!

3 Replies to “Building Blox: Week 7 – Ground floor taking shape”

    1. Hi T, thanks for the message =-]
      Yep the contractors do like to keep it nice and tidy!
      The boyband don’t speak the best English and not sure how health and safety feel about videoing at heights, but I’ll try!

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