St Albans · Hertfordshire

Builders You Can
Actually Trust.

Garage conversions, house extensions, loft conversions and full renovations across Hertfordshire. Over 40 years of combined experience. Fixed-price quotes. 80% of work comes from personal recommendations.

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Garage conversion with French doors — Stag Builders Hertfordshire

Who We Are

Trusted by Hertfordshire Homeowners

Stag Builders of Hertfordshire LLP is a highly trusted, family-run building company based in St Albans. We specialise in garage conversions, house extensions and full home renovations across Hertfordshire. Homeowners in St Albans, Hertford, Welwyn Garden City and surrounding areas choose us for our craftsmanship, reliability and strong local reputation.

Our partnership brings more than 40 years of combined trade experience — one partner with deep traditional expertise, the other with modern construction knowledge, up-to-date building regulations and current industry techniques. Every project benefits from both.

Our team is carefully vetted, highly skilled and committed to exceptional results. We focus on practical, beautifully finished living spaces that add real value and long-term durability to your home.

Federation of Master Builders TrustMark Government Endorsed National Federation of Builders

What We Do

Building Services Across Hertfordshire

Skilled tradesmen for every aspect of your build — from single-storey extensions to complete property renovations.

House Extensions

Single and double-storey rear extensions that create striking new spaces, enhancing both the aesthetic appeal and value of your property.

Garage Conversions

Transform your underused garage into a functional living space. Packages from £14,950 exc VAT. Office, bedroom, gym, playroom or annexe.

Loft Conversions

Dormer, hip-to-gable, Velux and mansard conversions. Structural engineers and experienced architects from first design to completion.

Kitchen Renovations

Complete kitchen transformations and extensions. Thoughtful layouts and meticulous finishes that make the heart of your home stand out.

Patios & Decking

Paving and decking areas designed for years of outdoor enjoyment. From choosing the perfect spot to selecting materials and laying the finished space.

TV Media Walls

Bespoke TV media walls designed and built to your specification — a statement feature that transforms any living room.

Also Available

Home Renovation

Bathroom Renovation

Painting & Decoration

Plastering & Rendering

Roofing

Demolition & Groundworks

Carpentry

Landscaping

Real Projects

Our Work Across Hertfordshire

Every photo below is a completed project by our team. Thoughtful layouts, meticulous finishes, genuine passion for the craft.

Garage Conversion — St Albans

Inside garage conversion — new living space

Garage conversion retaining the existing door, with new French doors cut through from the living room, garden side access and a rear window.

Single-storey rear house extension — St Albans

Kitchen renovation & extension — Hertfordshire

Why Stag Builders

What Sets Us Apart

Fixed-Price Quotations

We provide fixed-price quotes so you can budget with confidence. No surprise costs, no moving goalposts. What we quote is what you pay.

Vetted, Skilled Tradesmen

Every member of our team is carefully vetted and highly skilled. We take full responsibility for all work carried out on your property.

Family-Run, Local Business

We're a genuine family-run local business. Over 80% of our projects come from personal recommendations — the trust of our clients is our reputation.

All Work Guaranteed

First-class aftercare service and guaranteed workmanship on every project. We stand behind what we build, long after the job is done.

Building Regulations Compliant

We manage all planning permission and building regulation requirements so you don't have to. Fully compliant construction, always.

Free Site Visits

Book a free site visit and we'll come to your property, understand your requirements, and provide a detailed fixed-price quotation — no obligation.

Coverage

Local to You in Hertfordshire

Based in St Albans, we serve homeowners throughout Hertfordshire. Our local knowledge and strong network of suppliers means faster builds and better value.

St Albans

Hertford

Welwyn Garden City

Kings Langley

Harpenden

Radlett

And throughout the surrounding Hertfordshire area. Not sure if we cover your postcode? Give us a call.