Mortgage Budget Planner
At a glance
Use this planner to build a realistic self-build budget: break costs into plot/acquisition, build, professional & statutory fees, access/servicing, and add a sensible contingency (often 10–15%). Track a running total, estimate the mortgage you’ll need, and sense-check cashflow against stage payments. If in doubt, speak to a specialist broker (e.g., BuildStore or The Lending Channel) and consider an eco-focused lender (e.g., Ecology).
Reviewed by Alasdair Stephen, Managing Director, and Neil Stephen RIAS, Director.
Common Questions
What does the Mortgage Budget Planner calculate? ›
It helps you structure a total self-build budget, see where the money goes, and understand your likely mortgage requirement and cashflow before you commit.
How do I use the Mortgage Budget Planner? ›
Enter costs under each heading: acquisition, build, professional/statutory, and servicing. Add contingency and allowances (landscaping, furniture, VAT). Then enter your own cash to see the estimated mortgage requirement.
Which costs should I include in my self-build budget? ›
Typical headings: land, legal, stamp duty, searches; kit/structure, groundworks, externals, M&E, fit-out, kitchens/bathrooms, prelims; architect/agent, engineer, planning, building control, surveys, warranty, insurance; access, water, power, drainage, telecoms.
How much contingency should I allow? ›
Normally 10–15% of pre-contingency costs. Use the higher end if your site has unknown ground conditions, steep access, or complex servicing.
How do stage payments affect my budget? ›
Lenders release funds at milestones (land, foundations, structure, watertight, completion). Align your costs and contractor payments with these stages to avoid cashflow gaps.
What’s the difference between valuation-based and cost-based stage payments? ›
Valuation-based: funds released after inspection of completed works. Cost-based: stage payments pre-agreed and released in advance (via specialist products), giving more predictable cashflow.
How do I estimate interest during the build? ›
As a guide, apply your APR to ~50% of the peak borrowing (the average drawn balance) multiplied by build months/12. The planner provides an indicative figure—your broker can give precise calculations.
Should I include VAT in my self-build budget? ›
Add any non-reclaimable VAT in the VAT field. Many new build costs are zero-rated or reclaimable—check rules or ask your accountant. Always budget cautiously if unsure.
How much cash or deposit will I need? ›
Varies by lender. Expect to put cash towards land and early works, plus a contingency. A broker can confirm deposit and maximum borrowing for your situation.
Which documents support a self-build mortgage application? ›
Planning approval, drawings/specification, build programme, detailed cost plan or contract, surveys (GI/topo/percolation), warranty, site insurance, and details of your build system (SIP or CPS with BOPAS accreditation).
Can I get a mortgage on a SIP or CPS HebHome? ›
Yes. SIPs are widely accepted with a 10-year warranty. CPS homes are mortgageable and HebHomes’ system is BOPAS accredited, giving lenders added assurance.
How do I budget for access and servicing? ›
Obtain early quotes for access roads, water/boreholes, power, drainage (mains/septic/plant), and telecoms. These costs can make or break site viability.
What about budgeting in Ireland? ›
Irish self-build mortgages pay in stages. Lenders usually require full planning, a fixed-price contract or cost plan, and a recognised 10-year warranty (e.g., HomeBond, Global). Same principles apply: allow for servicing and contingency.
When should I speak to a Quantity Surveyor or mortgage broker? ›
Use this tool for a rough guide, then commission a QS for detailed costs and speak to a broker (BuildStore, The Lending Channel) early to align finance with your build.
What if my budget exceeds my borrowing capacity? ›
Options include reducing area/spec, phasing externals, reworking servicing, or switching to cost-based stage payments. A broker can advise on alternatives and products.
Which self-build budgeting mistakes should I avoid? ›
Underestimating ground or servicing costs, omitting professional fees, assuming valuation-based funds cover deposits, and setting contingency too low. Update your plan as quotes firm up.
£
Take the Next Step
Create your free project account to explore floor plans, pricing tools, practical guides and resources for planning your HebHome.
Create Your Free Project Account
