Project costing - free
Single-storey rear / side extension: cost a whole project, stage by stage
A ground-floor extension: design, foundations, walls, roof, openings, services, finishes. JobBosh lays the project out as 20 stages: 13 are calculated by their own recipes from your measurements; the rest - design, steel, windows, certificates - are priced from a quotation or a figure you already hold, and it says so until you have it.
The stages
| Stage | Work | How it is costed | Enquiries it may need | |
|---|---|---|---|---|
| Survey, design and engineering | Architect / technologist drawings and structural engineer's calculations | Design and engineering fees - by quotation | Architect / architectural technologist, Structural engineer | usual |
| Permissions and notices | Planning / permitted development check, building control application, party-wall notices where applicable | Application fees and party-wall surveyor where applicable - by quotation | Party-wall surveyor | optional |
| Site set-up and protection | Site set-up: welfare, protection, skip and scaffold licences where the highway is used | by someone else's figure | Skip hire, Scaffolding | usual |
| Demolition / strip-out | Remove rear wall opening / existing structures | calculated by its recipe | - | usual |
| Groundworks and drainage | Drainage diversion / new connections | calculated by its recipe | - | usual |
| Foundations | Strip foundations to the engineer's depth | calculated by its recipe | - | usual |
| Groundworks and drainage | Ground-floor slab with insulation | calculated by its recipe | - | usual |
| Walls and openings | Cavity walls in facing brick and block | calculated by its recipe | - | usual |
| Structural work | Steel beam over the opening to the existing house | Steelwork supply, fabrication and crane/lift - by quotation | Steel fabrication | usual |
| Roofing | Pitched roof (or flat roof: swap the recipe) | calculated by its recipe | - | usual |
| Windows and external doors | Windows and bi-fold / french doors | Windows and doors supply and fit - by quotation | Windows and doors supply and fit | usual |
| First fix (carpentry, plumbing, electrics) | Electrical first fix | calculated by its recipe | - | usual |
| First fix (carpentry, plumbing, electrics) | Heating extension | calculated by its recipe | - | usual |
| Plastering and finishing | Board and skim walls and ceiling | calculated by its recipe | - | usual |
| Flooring | Floor finish | calculated by its recipe | - | usual |
| Decorating | Decorate | calculated by its recipe | - | usual |
| Decorating | Woodwork | calculated by its recipe | - | usual |
| External works | Patio / paths | calculated by its recipe | - | optional |
| Commissioning and inspections | Building control completion certificate, electrical and gas certificates | Certificates and inspection fees | - | usual |
| Snagging and handover | Snagging and handover | by someone else's figure | - | usual |
What you get
- Every stage's quantities and hours from its recipe, priced at your rates and prices; the specialist stages as named unknowns until a quotation or your figure resolves them - never a guess
- Supplier enquiries drafted from the job's facts for scaffold, skips, steel, windows, the professions - approved by you before anything is sent, replies compared like for like
- Travel, parking and road charges from the dated catalogue; the site questions (welfare, power, water, access, protection, waste) as lines, enquiries and sentences in the document
- A phased, branded quotation itemised by stage that reconciles to the penny, with provisional allowances shown apart, accepted on a secure link; variations recorded against it