G’day. This is Matt Cornell from Cornell Engineers. This is a waffle slab inspection that we did a little while ago and I wanted to go through and put some words to it to let you know what we’re looking at during this inspection.
So here we go coming in from the front I’ll just pause it there and explain some of these things.
The white things that you can see are the polystyrene waffle pods. They are the voids in this soon to be poured concrete waffle slab. The waffle pods are about a one metre x one metre squares. They’re sort of semi- hollow underneath. They’re not solid polystyrene but on top they’re solid. The space between waffle pods is about 110mm wide.
Hi! I’m Matt Cornell – owner and director of Cornell Engineers – a Brisbane based structural engineering consultancy.
If you’re looking for a structural engineer for your new home project, I think Cornell Engineers can help you.
We’ve been providing structural engineering for new houses in Queensland since 2003 – so read on and we’ll get you set up!
What We Need from You
It’s rare that you’ll start the new home design process with your engineer. There’s a few things you’ll need to do before you come to see us
I’ll list them out first and then explain how and why you need to get these things sorted before you engage us:
Architectural plans or building designer’s plans.
A soil test.
The drawings prepared by an architect or a building designer include
floor plans (which show how big each room is and where it is in the your new home;
site plans (which show where your building will be on your allotment);
elevations (which are the side views); and
cross-sections (imaginary views through your house if your house was cut in half).
These drawings tell us what you want your home to look like. They tell us whether you have a slab on ground or a timber floor on stumps, how tall your home is, what the walls and roof are clad with and where your internal and external walls are.
We use this information to work out:
the wind loads on your building so that we can design the bracing walls;
what your floor will be made of so that we can design and specify the slab and/or timber framing; and
what the major structural elements are and how they will be connected.
whether there are any issues on your site that need to be accounted for such as council sewer mains, retaining walls, steep slopes and large trees.
We like to receive the architectural /building design drawings in pdf format as well as an electronic drawing format such as dwg, dxf or pln format so that we can extract the drawn-to-scale lines that make up the floor plans and elevations. If your designer prepared 3-d views of your finished house we’d like those too so we can visualise the aesthetics of your finished product
A Soil Test
We need a copy of your soil test results before we can finalise your footing and slab design.
When you engage Cornell Engineers to do your structural engineering, this is what you get:
Footing and slab plans and details. We calculate how wide and deep your footings need to be and then provide enough details so that your builder knows how to build them.
Wall framing details. We tell you how to make the walls (whether they be timber, brickwork, concrete masonry or any combination) and how everything is connected.
Wall bracing plans. We’ll specify panels of plywood bracing walls to resist and transfer wind forces from the walls to the footing and slab.
Roof framing plans. We specify the size and position of lintels, roof beams and rafters. We leave truss design to the experts that supply your trusses. The plans show the sizes and any special connection details.
Specifications specific to your project. Our drawings start with a set of notes that are refined so that they are applicable to your project.
Form 15 design certificate. This is the standard form specified by the Queensland Department of Housing and Public Works that we prepare and issue when we send our finalised drawings. Get more information on DHPW forms here.
We work hard to show this information as clearly as possible so that there are very few surprises during construction. We work hard to make sure your house is as easy to build as possible because this is how we save you money.
Once we send you a quote, you just need to tell us that our quote has been accepted to get us started. We’ll work directly with your architect or building designer, help you get a soil test if and when you need one, prepare and issue the structural engineering drawings to you by email, and help you find a good, local certifier and builder.
If you have any more questions, contact us here. We’re looking forward to getting started on the structural engineering for your new home!
I took the time to read right through the Softley v Metricon Homes Pty Ltd decision that was published by VCAT on 11 December 2014. Metricon was ordered to pay costs to knock down and rebuild the Softley’s house.
I was editing some of my waffle slab posts when I suddenly realised that the amount of slab movement in the Softley’s home was a lot less than the amount of slab heave and movement I have inspected and reported on in Queensland – even recently. Continue reading The Inevitable Failure of Waffle Slabs→