Tender drawings from us start at from £945. The package takes your approved drawings and adds the construction detail and schedules a builder needs to price the job, so that every quote you receive is for the same work.
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Most owners meet this problem after their first set of quotes. One builder allows for basic windows and another for premium ones, one includes the tiling and another does not, and the totals say nothing about which builder offers better value. A tender pack removes the guesswork by fixing what is being priced.
Why do quotes differ so much without one?
Because a planning drawing and a building regulations drawing both leave choices open. A planning drawing shows what the extension looks like and where it sits. A building regulations drawing shows how it complies: sections, insulation, structure, fire and drainage. Neither says what the kitchen floor is made of, how many sockets there are or what the window frames cost.
So each builder prices their own idea of the job. The tender package closes those gaps in writing, so the builders quote against one scope and you compare like with like. Where something cannot be decided yet, it is listed as a provisional sum, with the allowance stated.
What is in a tender package?
Three things. Construction details at a scale a builder can work from: wall and floor build-ups, junctions, openings, roof edges and thresholds. Schedules, which are lists of windows, doors, finishes, ironmongery and fittings with their specification. And a scope note, which says what the price must include and what is excluded.
It sits on top of the earlier work. If you bought the extension plans package, the model already exists and the tender set is drawn from it. If you have drawings from someone else, send them and we tell you what we can build on and what needs a survey first.
How does it relate to building regulations?
It does not replace them. Before building work starts you must give a building notice or an application with full plans (regulation 12), and you can use your council's building control or a registered private approver (GOV.UK). Our building regulations drawings cost post covers that set.
The sensible order is building regulations first, then the tender pack, because the builders should price what building control will accept. Tender detail that conflicts with the approved drawings means a variation later.
Do I need one on a small job?
Not always. A single-room alteration with one trusted builder may need only the building regulations set and a conversation. A tender pack earns its fee where several builders are invited to quote, the budget is large, or the finishes carry the cost.
There is also a legal angle for domestic clients. The HSE says that on a single-contractor project the client duties under the Construction (Design and Management) Regulations 2015 pass to the contractor, and on a project with more than one contractor they pass to the principal contractor. A designer can take them on only under a written agreement with you (HSE). We do not take on those duties as part of the tender package; ask us before you assume we do.
What does it not include?
The builder's price, a contract, or any judgement on which builder to choose. We do not tell you who to pick. Comparing the quotes is yours, and a single scope makes it far easier.
Frequently asked questions
Can I use the same pack for planning? No. Planning needs the application drawings, which are a separate and earlier set. Our planning drawing service covers it.
How many builders should I invite to tender? Three is a common choice because it gives a range without making the exercise slow, but that is a general habit, not a rule. Invite the number you can compare properly.
Does the pack include a contract? No. A contract between you and the builder is a legal document we do not draw up. The pack defines the work for the contract to refer to.
What if a builder wants to change the specification? That is normal and useful. A builder who proposes a substitute is pricing the same job against a stated alternative, and the schedule shows exactly what changed.
