How to price a fencing and decking job without losing on groundwork

How to price a fencing job without underquoting groundwork

The fastest way to price a fencing and decking job properly is to split the quote into four blocks - groundwork and post setting, materials, above-ground labour, and waste/access - and price groundwork on a worst-case assumption for the soil, not a best-case one. Most fencing and decking jobs don't lose money on the timber or panels; they lose money on what's under the lawn: compacted fill, old concrete, tree roots, or a water table that turns post holes into a pumping job. Quote the visible work accurately and protect the groundwork with a clear assumption and a contingency clause, and the job stays profitable even when the ground doesn't cooperate.

Why groundwork is where fencing quotes actually fail

Panels, posts and decking boards are easy to price - they're a fixed quantity at a fixed unit cost, and most contractors have that part down cold. Groundwork is where the guessing starts, because you genuinely can't see what's below the surface until you're digging it. A single garden can have three different soil types along one fence line: clay near the house, builder's rubble near an old extension, and soft fill near a boundary that was regraded a decade ago.

The temptation is to quote one "post hole" rate for the whole run and hope it averages out. Sometimes it does. But when it doesn't - when you hit a slab of old patio base two posts in - that single bad hole can cost you more time than the other nine combined, and there's no line item to absorb it.

Build the quote around four separate blocks

Rather than one lump sum, price the job in blocks that can each be checked and adjusted independently:

• Groundwork and post setting - digging, post removal if replacing an old fence, concrete or post mix, levelling, and dealing with obstructions.
• Materials - posts, panels or deck boards, joists, fixings, postcrete, gravel boards, and any ironmongery.
• Above-ground labour - fitting panels, building the deck frame, laying boards, fitting trims and balustrades.
• Waste and access - skip or tip runs for old fencing and spoil, plus any access charges for narrow side gates or sites with no vehicle access.

This structure does two things. It makes the quote easier for the customer to understand line by line, and it stops a groundwork overrun from quietly eating into the labour or materials margin, because each block has its own number.

Pricing groundwork realistically

For groundwork specifically, build in a soil assumption rather than a flat day rate. A reasonable approach:

1. State the assumed ground condition in the quote - for example, "priced for standard garden soil, free of major obstructions, to a depth of 600mm."
2. Price digging per post at a standard rate, based on typical soil for the region and time of year (wet clay in winter digs very differently to dry soil in summer).
3. Add a contingency line for hard ground, stated as a day rate or per-post surcharge that applies only if you hit rubble, roots, or rock - and tell the customer upfront that this may apply.
4. Check for old foundations or slabs before quoting, where possible, by probing a few spots with a bar on the site visit rather than relying on a visual look at the grass.

For decking specifically, also check ground levels and drainage before pricing the substructure. A deck built on a slope or over poor drainage needs more joists, more posts, or a different foundation approach (concrete pad vs screw pile vs post-and-base), and that decision changes the groundwork cost significantly. Spotting it at quote stage, rather than once the frame is half built, is what keeps the number honest.

Decking adds its own groundwork variables

Fencing groundwork is mostly about post holes. Decking groundwork is more involved, because the whole structure sits on a substructure that has to handle load, drainage and sometimes building regulations depending on height and location. Before pricing a deck, check:

• Ground slope and whether it needs levelling or stepped foundations
• Drainage - standing water under a deck causes problems within a year or two
• Height above ground, which affects whether balustrades or steps are required
• Soil bearing, particularly on clay or recently backfilled ground, which may need deeper or wider footings

None of this needs to turn into an engineering report for a standard garden deck, but a five-minute check with a spade and a spirit level on the site visit is cheap insurance against a groundwork surcharge mid-job.

Use the site visit to lock in your assumptions, not just your measurements

A lot of fencing and decking quotes are priced from measurements alone - fence line length, deck footprint - without a written note of ground condition. That's the gap that causes disputes later, because "the ground was harder than expected" sounds like an excuse to a customer if it wasn't flagged at quote stage.

Write the assumption into the quote itself: soil type assumed, depth assumed, what triggers the contingency rate, and who decides if it applies (ideally agreed on-site with the customer present, not after the fact). This is also where an AI quoting tool can help - turning site visit notes into a structured quote with groundwork, materials and labour as separate, clearly priced lines, rather than a single number typed up from memory that night. For a broader look at structuring quotes so they survive once the job starts, see our guide on how to quote a construction job.

Frequently asked questions

How do I price post holes for a fence?

Price digging per post at a standard rate based on typical local soil, state that assumption in the quote, and add a per-post or day-rate contingency that applies only if you hit rubble, roots or rock.

Should decking and fencing be quoted as one job or separately?

Quote them as separate blocks within the same document - they have different groundwork, material and labour profiles, and combining them into one number makes it harder to track where a job actually lost or made money.

What's the biggest hidden cost in a decking quote?

Drainage and ground levels. A sloped or poorly draining plot often needs a different substructure than a flat, well-drained one, and that difference can change the groundwork cost substantially.

How do I avoid disputes over groundwork surcharges?

State your ground condition assumption in writing at quote stage, define exactly what triggers the contingency rate, and ideally agree it with the customer on-site before you start digging.

Does old fence removal need its own line item?

Yes - removing and disposing of an old fence or deck is a separate cost from building the new one, and it should be priced and shown separately so the customer sees what they're paying for.

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This article was written with AI assistance and checked for accuracy by Carl and Martin before publishing.

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