How to write a quote for a garden decking installation (with a real worked example)

A mate of mine in Leeds quoted £2,400 for a 5 by 4 metre deck in one line on a text message: "decking, 20 square metres, supply and fit". On day one he found the back lawn sat on clay that held water. The customer wanted steps down to the patio. The first board had to be cut round a concrete fence post. None of it was on the quote, so he did the lot and ate about £700.

The deck wasn't the problem. The quote never said what was under the boards, what was added on top of them, or where the job stopped. This guide shows how to write a decking quote so those answers are on paper before the first post goes in.

Survey the garden before you price anything

Walk the garden with the customer and a tape. Four things go in your notes before a number goes on paper.

• Area and shape. Measure the footprint and mark every cut: trees, posts, the corner by the shed, the downpipe.
• Height. Ground level to the top of the finished board. A deck no more than 300mm above the ground is usually permitted development, but check the Planning Portal or the local authority, especially in a conservation area. Where the drop is more than 600mm, Approved Document K expects a guard.
• Ground. Dig a test hole. Clay, topsoil, old patio or made ground each change the groundwork. Water sitting in the hole tells you the frame needs a membrane, a gravel base and air underneath.
• What is underneath and nearby. Drain covers, inspection chambers, buried cables, a soakaway. Never box in an inspection chamber without a removable hatch.

Take photos with the tape in shot. When the customer says "it was never this wet", you have the date and the picture.

Then ask the two questions that move the price most: which boards (treated softwood, hardwood or composite), and whether there are steps, a handrail, lighting or a pergola. Write the answers on the quote, not in your head.

Split the quote the way the job runs

One lump sum is quick to write and hard to defend. Break it into the stages the customer can see happening in their garden.

1. Clearance and groundwork. Turf off, levelling, membrane, gravel, skip.
2. Frame. Posts or pads, bearers and joists, with the timber use class named. Anything in ground contact should be Use Class 4.
3. Boards. Product, size, finish, lay pattern and waste allowance.
4. Extras. Steps, edging, fascia, handrail, lighting.
5. Labour. Days and number of people, not a vague "labour".
6. Delivery, disposal and your margin.

Put the board waste on the quote as a number. A straight lay wastes around 10% and a diagonal or herringbone pattern nearer 15%. A customer who sees 22 square metres on a 20 square metre deck doesn't ask why.

Name the product. "Decking boards" is not a specification. "28 x 144mm pressure-treated softwood, reeded face, brown" is. If the merchant substitutes something, you are changing the quote, not the customer's mind. The maths behind your day rate is in how to price a trade job.

A worked example: 5 by 4 metre low-level deck

Adam Wójcik trading as Wójcik Landscaping is pricing a 5 by 4 metre deck, 20 square metres, 250mm above a lawn that drains badly. Pressure-treated softwood, straight lay, two steps to the patio, no handrail because the drop is under 600mm. Two people for three and a half days.

• Skip hire and turf disposal: £240
• Weed membrane and 50mm gravel base: £180
• Frame timber (joists, bearers, Use Class 4 posts): £540
• Concrete, ballast and footings: £85
• Boards, 22 square metres at £28, includes 10% waste: £616
• Screws, brackets and end-grain treatment: £95
• Steps, two treads, materials: £110
• Merchant delivery: £45
• Labour, 6.5 person-days at £210: £1,365
• Subtotal: £3,276
• Contingency and profit at 10%: £327.60
• Quote, rounded: £3,600 before VAT

If Adam is VAT registered, VAT at 20% adds £720, so the customer sees £4,320. Decking in an existing garden is standard rated.

Quoted the Leeds way, at £2,400, the same job leaves the builder well short. Here the risk lines are visible: the skip, the gravel, the waste. The gravel base is the reason a deck on wet clay lasts, so it shouldn't be the first line dropped when the customer says the number is high. Take out the steps or downgrade the boards if you must, and let the groundwork stand.

Exclusions, provisional sums and the weather

Write what is out of the price, in plain English.

• Moving or removing sheds, fences, planters and trees.
• Diverting drains, or building over an inspection chamber without a hatch.
• Electrical work for lights or sockets, which needs a Part P registered electrician.
• Staining or oiling, unless you have priced it.
• Anything the customer adds after acceptance, which is a variation priced in writing first.

Then add a provisional sum for the ground. Something like: "Ground is assumed to be firm clay or topsoil to 300mm. If we find old foundations, rubble or soft ground, extra excavation and hardcore is charged at £210 a day per person plus materials at cost, agreed in writing before we carry on. Any unused provisional sum comes off the final invoice."

Add one sentence on the weather. Timber doesn't mind rain but wet clay and fresh concrete do, so say dates move if the ground is waterlogged, and that you leave the site safe overnight with no open holes.

Payment stages that match the job

A deck is a materials-heavy job, so the first payment has to cover the timber. On the £3,600 example, three stages work.

• £1,080 (30%) on acceptance, to order the timber and the skip.
• £1,440 (40%) when the frame is in and the boards are on site.
• £1,080 (30%) on completion, after the customer has walked it and signed it off.

Put the percentages and the triggers on the quote. How much is fair to ask upfront is in the guide on deposits, and the thinking behind the other two stages is in stage payments for trades. Send the final invoice the same day you finish.

What NOT to do

1. Don't quote a flat rate per square metre. A figure that ignores the ground, the height and the steps is a guess with a number on it.
2. Don't skip the groundwork. A deck on bad ground is a deck you rebuild in four years, with your name on it.
3. Don't leave the board off the specification. Name the product, size and finish so a substitution is a decision, not an accident.
4. Don't build over drains or inspection chambers. Fit a hatch or get the customer's written sign-off to leave the cover buried.
5. Don't let steps, rails and lights creep in as "while you're here". Price them as a variation the same day.

The short version

Measure the garden and dig a test hole before you price. Put the groundwork, frame, boards, extras and labour on separate lines, with the board named and the waste shown. Use a provisional sum for what is buried, write the exclusions in plain English, and tie the payments to stages the customer can see. That leaves fewer reasons for a row on the final invoice.

Frequently asked questions

How much does it cost to build decking in the UK?

It depends on the size, the height, the boards and the ground. The worked example, a 20 square metre low-level deck in pressure-treated softwood with two steps, comes to £3,600 before VAT including groundwork, materials, labour and waste. Price your own job from your own measurements, not from a headline figure.

Do I need planning permission for decking?

Usually not for a deck that sits no more than 300mm above the ground, but it depends on the property. Check the Planning Portal or your local authority first, especially in a conservation area, on a listed building or where the deck is higher than 300mm. Put what you found on the quote.

Do I need Building Regulations approval for decking?

Most low-level garden decks do not, but a raised deck needs a guard where the drop is more than 600mm under Approved Document K, and a deck that runs across the damp-proof course of the house can cause damp. If you are unsure, ask the local authority Building Control before you price.

Should I use treated softwood, hardwood or composite boards?

Treated softwood is the cheapest and does the job if it has air underneath and gets looked after. Hardwood and composite cost more and last longer. Whichever you choose, name the product on the quote and say who pays if the customer changes their mind after the boards are ordered.

How long does it take to build a deck?

A 20 square metre deck with a simple frame is around three to four days for two people once the ground is clear, with the weather and the ground conditions being the main variables. The worked example allows 6.5 person-days. Say on the quote that dates move if the ground is waterlogged.