To get a construction estimate you need the architectural plans: the floor plans, elevations and sections, as PDFs. They're the one upload our estimate form requires on a house. The engineering, soil report, site plan and your selections each let us price more of the job off what you've sent. Where the drawings leave something out, the estimate carries an allowance for you to confirm. Site work like tree removal or retaining walls is listed as excluded instead. The more of the set you send, the less the estimate has to allow for.
The plans every estimate is measured from
The floor plans, elevations and sections drive the takeoff. Floor plans give us the floor area, the wall lengths and every room. The elevations add wall heights, openings and cladding. Sections show the ceiling heights, the roof pitch and how the floor, walls and roof go together.
On our sample estimate for a single storey home, the waffle pod slab is priced at 198.32 m2, the wall frames at 194.2 m2 and the roof trusses and tiles at 218.2 m2. The bricks come to 6,656, worked out from the net wall area. Each of those lines is marked From the plans.
A window and door schedule and an electrical plan are often sheets in the architectural set. The example plan set the Australian Building Codes Board (ABCB) publishes on the NCC website lists both in its drawing index. Upload them with the architectural plans. Our sample prices its windows and sliding doors as one line of 21.1 m2 and counts 21 double and four single general power points and 18 downlights off the plans.
What the engineering, soil report and site plan add
On a house, the form's second box, Civil and survey, takes all three, along with the contours and the drainage design.
The engineer's slab and footing drawings set the slab, the footings and any piers. Without them, the slab type and soil class you give on the form fill the gap. Work an engineer sizes, like the bored piers on our sample, can go in as an allowance.
Your soil report names the site class. The form lists all seven, from Class A (stable, mostly sand or rock) to Class P (a problem site with fill, soft soil or landslip). Leave it at Not sure yet if the report isn't done. Your soil report or energy report also gives the wind rating the form asks for.
The site plan, contours and drainage set the site works. On our sample the sewer and stormwater drainage and the connection to the kerb and channel come off the plans, while the cut and fill is an allowance of $909. Site levels are what pin the cut and fill down.
A scope of works or your selections lets the estimate match the finish level in the kitchen, bathrooms and flooring. The third box takes it, along with a project specification or a finishes or fixtures schedule. Fittings nobody has picked yet stay allowances: on our sample, the light fittings are a $2,360 allowance.
How to upload your drawings
Plans is the second step on our estimate form, after the Job step. A house has three boxes:
- The architectural plans box is the one you have to fill. It takes the floor plans, elevations and sections, plus the window and door schedule and the electrical plan if the set has them.
- The civil and survey box is optional on a house. It takes the site plan, contours, drainage, the engineering and the soil report.
- The scope of works or selections box is optional too. It takes the specification or your client's selections.
Every file has to be a PDF of up to 50 MB. Each box takes several files, up to 150 MB for the whole job. A file in another format is turned back with a note to export it as a PDF.
Our terms ask you to name the drawing revision you want priced and to tell us promptly when the drawings change. If the set holds more than one revision, say which one in the Anything not on the plans box on the last step.
What the form asks when a drawing is missing
The third step, Build Details, asks the questions the drawings usually answer. Every question on that step is optional.
On a house, the first card covers how the building is built: the slab or footing type, the construction type, the soil class, the roofing, the garage walls and the temporary fencing. Its note reads "If you attached the engineering, the slab is read off it. These fill the gaps the drawings leave."
The site card asks about trees to remove, an existing structure to demolish, a sloping site where retaining is likely, a water tank and the crossover. Work that isn't ticked and isn't on the plans stays out of the estimate and is listed as excluded.
The services card asks things like heating and cooling, gas or full electric and the wind rating. The finishes card covers things like the kitchen cabinets, the wall and floor tiles, the staircase and the balcony balustrade. Leave a finish blank and we assume the standard.
The last step has a box for anything not on the plans, like site access, the spec level, or anything your client is supplying or has excluded.
How a missing drawing shows on your estimate
Every priced line on our estimates carries one of three marks. The key printed under the trades reads "From the plans: measured off your drawings. Allowance: a set amount to confirm. Quote: needs a trade quote."
On the line-by-line of our sample, 217 lines are From the plans, 78 are Allowance and one is a Quote. The slab cost centre shows the first two side by side. The waffle pod slab, 198.32 m2 at $141.60 a square metre, is From the plans. The bored piers are an engineer design allowance of 41.25 lineal metres at $188.80. The extra bulk concrete is another allowance, 5 m3 at $472.
Conditional site work is left out unless something shows it's needed. Tree removal, demolition, retaining walls, a stormwater detention tank, a pump and a new crossover are only priced when the plans show them or you note them on the form. Otherwise each one is listed under Excluded from this estimate, above the reason "Not shown on the plans and not noted on the enquiry form". Our sample lists all six that way.
We check every estimate before it's emailed to you. Our terms describe an allowance as an estimate for an item that isn't fully specified or priced yet. Check the big ones against trade quotes before you sign a building contract or submit a tender.
Can you get an estimate from preliminary drawings?
Yes, you can order an estimate on early drawings. Wherever something hasn't been drawn or selected yet, the estimate carries an allowance for it. Site work the drawings don't show is listed as excluded.
A plan set changes as a job moves from planning to construction. The revision table on the ABCB example set shows one path, from a town planning draft through the planning application and its revisions to a construction issue set of working drawings. Working drawings are the set a builder builds from. The earlier the set you send, the more of the estimate goes in as allowances.
Our usual turnaround of 48 hours (two business days) is for a standard, fully documented job. A heavily revised or incomplete set can need longer. If yours does, we'll let you know and give you a new date.
When the drawings change after the estimate is done, a new revision can be a variation. The fee covers one round of minor clarifications asked within 10 business days of delivery, as long as the drawings haven't changed.
Drawings for duplexes, units, apartments and commercial jobs
A dual occupancy or duplex uploads the same three boxes as a house. The other job types change what the form asks for.
- On a multi unit or townhouse development, the site plan, civil and survey box is required. Without the site or landscape plan and the drainage design, the demolition, driveway, crossovers, drainage and fencing can't be priced. The form also asks whether the drawings cover one dwelling type or the whole site. Name each dwelling type the way the drawings name it, because that's how the printed areas get matched to the right dwelling.
- An apartment building gets a fourth box for the structural engineering, since the floor system on every level is read off it. Without it the structure is carried as allowances and the estimate says so. The site and civil drawings are optional on apartments. Without them, the site works, car park, crossovers and retaining are scaled off the architectural set and flagged.
- A commercial job asks which consultant drawings you have for civil and stormwater, hydraulic, mechanical, electrical and fire services. Each is answered Supplied, Not supplied or Not sure yet. Any package not supplied gets a benchmarked allowance. Our Commercial Estimating page has the fees.
- An extension or renovation asks which parts of the house are being redone inside their existing walls. Your answer is checked against the rooms the drawings mark as changed.
Not sure your drawings are ready?
Order with the architectural plans and any other drawings you have on our estimate form. Every priced line on the estimate tells you whether it came off your drawings, is an allowance to confirm or needs a trade quote. A standard estimate on a single storey home starts at $399 + GST. The full line-by-line is a complete bill of quantities and starts at $799 + GST. For houses, duplexes, townhouses and extensions, Residential Estimating has the fees for each of them.
