Before approving a construction estimate, check the scope of work, units, quantities, rates and formulas. Start with a few expensive or unclear line items. Check them against your measurements and price list, recalculate them by hand, and compare the results with the amounts in the estimate.
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What goes into a construction estimate?
A construction estimate shows the planned cost of labour, materials and equipment. For each line item, give a description, unit of measurement, quantity, unit rate and line total. That way, the contractor and client can check which work and materials are included in the total.
If you have yet to take measurements, mark the quantities as preliminary. Update the line items once you have the measurements so both parties can see how the estimate changed.
Unclear work descriptions
A line item labelled “wallpaper installation” leaves the type of wallpaper and whether wall preparation is included unclear. Specify the wallpaper type and the condition of the wall surface. If cleaning, levelling or priming is priced separately, list each as a separate line item. The client can then see what the price covers and discuss any additional work before it starts.
Incorrect units of measurement
For each line item, check that the quantity and rate use the same unit. If a material is measured in litres and priced per cubic metre, convert the quantity to cubic metres first: 1 m³ = 1,000 L. Use square metres for work measured by area and linear metres for work measured by length. Once the units match, multiply the quantity by the rate for that unit.
Estimating by area alone
A rate per square metre from an earlier project can give you a preliminary price range if the two sites are comparable in scope of work and finish standard. Before agreeing on the new project, measure the quantities on that site, confirm the scope of work and use current rates. This gives you an estimate for the actual site.
If you manage projects in 101, see how to reuse an estimate from a similar project (in Russian). Check the line items you transfer and update them to reflect the new site.
Missing work or quantities
Check the estimate against your measurements and the scope of work for each room or stage. If a task is missing, add a line item. If a quantity on an existing line is missing or incorrect, use your measurements to correct it. Then recalculate the total. If you have already discussed the estimate with the client, show them the changes to the scope, quantities and price before any additional work begins. Flag unclear line items separately so you can revisit them once you have the details.
Formula errors
In Excel, check that each row’s formula multiplies its quantity by its unit rate and that the range used to calculate the total includes all relevant rows. Recheck the formulas after inserting or deleting rows. Recalculate a few line items and the section totals by hand. If the amounts differ, check the cell references, units and ranges before sending the estimate.
You can also learn how to read an estimate and check its line items.
