On this page
- Why self-builders need a different guide
- Scenario A — Own site + new mortgage + HTB only
- Scenario B — Own site + new mortgage + FHS only
- Scenario C — Own site + new mortgage + HTB + FHS
- Scenario D — Buying a site, then self-building
- Valuation vs build cost — the single biggest self-build confusion
- The staged drawdown timeline
- Common self-build mistakes
- Next steps
Why self-builders need a different guide
Self-builders face a different set of questions from people buying a finished new-build from a developer. The two state schemes — Help to Buy and the First Home Scheme — both apply to self-builds, but the inputs they use, the way the money is released, and the way your funding stack is assessed are not the same as for a developer purchase.
If you are building on your own site (gifted, inherited, or recently purchased), the most common confusion is which figure each scheme actually uses: the approved valuation of the finished home, the build cost, or the site value. Get that wrong and the scheme estimate you carry into a meeting with your lender or solicitor will be inaccurate.
This guide walks through the four scenarios most Irish self-builders face, the valuation-vs-build-cost distinction, the staged drawdown timeline, and the mistakes that cost self-builders money or delay their build.
Scenario A — Own site + new mortgage + HTB only
This is the most common self-build pattern. The builder owns the site outright (often gifted by family). They take a self-build mortgage from a participating lender. They apply for Help to Buy through Revenue.
Eoin owns a half-acre site in rural Mayo gifted to him by his parents two years ago, currently valued at €55,000. His approved build cost is €295,000. His self-build mortgage approval is €235,000, and he has €25,000 in cash savings.
| Funding source | Amount |
|---|---|
| Site value (treated as equity) | €55,000 |
| Mortgage approval | €235,000 |
| Cash deposit | €25,000 |
| Subtotal before HTB | €315,000 |
Eoin’s subtotal already exceeds his €295,000 build cost. He does not have a funding gap. Does he still need HTB? Yes — HTB is not about closing a gap, it is about refunding income tax he has already paid. If he qualifies (first-time buyer, tax-compliant, 70% LTV self-build mortgage, build cost within the limit), Revenue can refund up to the smallest of: the cap, 10% of approved valuation, or his Income Tax + DIRT paid in the last four years.
For Eoin, HTB acts as a cash boost during construction (paid in stages to his bank account) that reduces what he has to draw from savings.
Scenario B — Own site + new mortgage + FHS only
Some self-builders cannot or do not qualify for HTB — for example, they have already used some of their tax refund history or fall short of the four-year tax record. They still want FHS support.
Méabh owns a site in Tipperary worth €45,000. Her approved build cost is €320,000. Her mortgage approval is €240,000, and she has €15,000 in cash. She does not qualify for HTB (she previously inherited a fractional interest in another property, disqualifying her under Revenue’s strict FTB test) but FHS treats her differently.
| Funding source | Amount |
|---|---|
| Site value | €45,000 |
| Mortgage approval | €240,000 |
| Cash deposit | €15,000 |
| Subtotal before FHS | €300,000 |
Funding gap: €320,000 − €300,000 = €20,000.
Without HTB, the FHS standalone cap is 30% of approved valuation = up to €96,000. The €20,000 gap is well within that. FHS supports the gap, taking an equity share of €20,000 ÷ €320,000 = about 6.25% of her home.
This is the cleanest FHS-only self-build pattern. The site closes most of the gap; FHS closes what’s left.
Scenario C — Own site + new mortgage + HTB + FHS
Combining both schemes is rarer in self-builds because the site itself often covers a large portion of the funding stack. But it does happen, especially in higher-cost build areas or where the site value is modest.
Tadhg has a site in Galway County worth €38,000. Approved build cost: €370,000. Mortgage: €275,000. Cash deposit: €18,000. HTB estimated refund: €22,000 (limited by his tax-paid record).
| Funding source | Amount |
|---|---|
| Site value | €38,000 |
| Mortgage approval | €275,000 |
| Cash deposit | €18,000 |
| HTB | €22,000 |
| Subtotal before FHS | €353,000 |
Funding gap: €370,000 − €353,000 = €17,000.
Because HTB is being used, FHS is capped at 20% of approved valuation = up to €74,000. The €17,000 gap is well within that. FHS supports the gap, with an equity share of €17,000 ÷ €370,000 = about 4.6%.
Scenario D — Buying a site, then self-building
Most self-build guides quietly assume the builder already owns the land. If you are buying the site and then self-building, your funding stack looks different — and the timing of HTB/FHS becomes more complex.
Niamh is buying a serviced site in Kildare for €80,000 and self-building for an approved build cost of €280,000. Her mortgage approval covers both site and build at €288,000. She has €40,000 in cash and an estimated HTB refund of €26,000.
| Funding source | Amount |
|---|---|
| Mortgage (covers site + build) | €288,000 |
| Cash | €40,000 |
| HTB | €26,000 |
| Subtotal before FHS | €354,000 |
Total cost: €80,000 + €280,000 = €360,000.
Funding gap: €6,000.
FHS could support the €6,000 if needed (small share of the home). But Niamh might also choose to absorb the €6,000 from extended savings rather than take on a shared-equity stake for such a small gap.
This pattern usually requires a lender that offers a single stage-released mortgage covering both the site purchase and the build — not all lenders do.
Valuation vs build cost — the single biggest self-build confusion
| Field | Where HTB uses it | Where FHS uses it |
|---|---|---|
| Site value | Counts toward your contribution but is not the HTB base | Counts toward your contribution but is not the FHS base |
| Build cost | Used by lenders for staged drawdown, but HTB does not use this directly | Used by FHS alongside approved valuation |
| Approved valuation | The lender’s final valuation of the completed home — HTB uses this for the 10% rule | FHS typically uses this and the build cost |
| Purchase price | Not applicable for self-builds | Not applicable for self-builds |
Practical rule: if the property type field on a scheme application form says "self-build", expect the lender’s approved valuation to be the figure that drives the HTB 10% rule. Expect FHS to look at both build cost and approved valuation when assessing the funding gap.
The staged drawdown timeline
Self-build mortgages typically draw down in stages tied to construction milestones — foundations, wall plate, roof on, first fix, second fix, completion. HTB and FHS need to be aligned with this timeline:
- Mortgage approval in principle — secured before any work starts.
- HTB application and approval — submitted alongside the build planning.
- First mortgage drawdown — usually at foundation stage. HTB refund may be released to your bank account at or shortly after this milestone.
- Subsequent mortgage drawdowns — at each construction milestone, verified by your engineer or architect.
- Final mortgage drawdown — on completion certificate.
- FHS funding — typically released around final stages, but the exact timing depends on your lender and the FHS portal.
Misaligning the timing — for example, expecting HTB cash at planning stage — is a common cause of cashflow problems for self-builders.
Common self-build mistakes
| Mistake | Why it costs money |
|---|---|
| Confusing build cost with approved valuation | HTB 10% rule uses approved valuation, not build cost |
| Forgetting site stamp duty | Site purchase usually attracts non-residential stamp duty |
| Underestimating contingency | Most self-builds overrun budget by 5–15%; HTB and FHS do not cover overruns |
| Expecting HTB as a single payment | Self-build HTB releases in stages, not as a lump sum |
| Assuming family-gifted land is HTB-relevant | The site itself is not HTB-eligible — only the build and Income Tax paid matter |
| Going to planning before approving cost | Budget overruns identified at planning add months of delay |
Next steps
- Check your tax-paid base for HTB: Help to Buy Explained.
- Check how FHS shared equity works long-term: First Home Scheme Explained and Service Charges Explained.
- Plan affordability across staged drawdowns: Mortgage Affordability Calculator and Mortgage Repayment Calculator.
- Confirm site-purchase stamp duty: Stamp Duty Calculator.
Frequently asked questions
Can I use Help to Buy if I'm building rather than buying?
Yes. HTB applies to selfbuilds as long as you meet the standard firsttime buyer eligibility and the build meets the scheme conditions. The main difference from a developer purchase is that the refund is released to your bank account in stages tied to construction milestones, not as a single payment at closing.
Does my gifted site count as part of my deposit?
Yes. The market value of your site — whether gifted, inherited, or purchased — counts toward your contribution to the build. Many selfbuilders find their site closes most of the funding gap before any scheme is applied, which can reduce or eliminate the need for FHS.
What's the difference between build cost and approved valuation?
Build cost is what it costs you to physically build the home. Approved valuation is what your lender values the completed home at on paper. The two are often close but not identical. HTB uses approved valuation for its 10% rule. FHS uses both numbers depending on the calculation step.
Can I use both HTB and FHS for the same self-build?
Yes, in some cases. The FHS cap reduces from 30% to 20% of approved valuation when HTB is also used, exactly as it does for a regular newbuild purchase. Many selfbuilders find their site value already covers enough of the gap that they don't need both.
What documents will my lender need for a self-build HTB application?
Typically: planning permission, fixedprice building contract or quantity surveyor cost report, lender valuation, your tax compliance record, and proof of title to the land. Your lender provides a full pack tailored to their process.
When during the build does the HTB refund actually arrive?
Usually after the first mortgage drawdown, which is typically at foundation stage. The exact timing varies by lender and by Revenue's stage processing. Plan your cashflow assuming HTB arrives in the earlytomid construction window, not at planning stage.
What happens if my build runs over budget?
You fund the difference from your own resources. Neither HTB nor FHS bridges an unapproved cost overrun. Most selfbuilders carry a 5–15% contingency in their own funds specifically for this.
Sources & references
Related calculators
Use these tools for the numbers behind this guide.