About Parnosa

Low-Carbon Retrofit

Fine Carpentry


A word from owner Jonathan Preston…

Parnosa is an old Hebrew word meaning ‘livelihood’. My late father used the name for his commercial interiors company in the 1960s, and I revived it in his name.

I’m a carpenter & joiner by trade – I did my apprenticeship in carpentry and joinery in London, working on high-value refurbishments and conversions. I founded Parnosa in 2014 with a decade of practical and management experience behind me.

Jonathan Preston, Parnosa DirectorI'm a lifelong environmentalist, so naturally sustainability and climate change are at the heart of what we do.

If you're considering substantial building work, please don't miss an opportunity to improve your building's energy efficiency. There might not be another opportunity for 20 years, and we're almost out of time.

Insulation isn't just a cost, it's a huge gain if specified & installed well. You'll be more comfortable and healthier, and the carbon footprint of a house can be reduced by a huge margin. So even if you're keeping a gas boiler, at least you can burn a lot less gas. Real-world payback period can be many years, but the other gains are immediate.

We reduce waste by careful pre-planning, design, ordering & board optimisation software. We have a battery-electric main van and we are committed to only using these vehicles in the future. Charging is provided by Ecotricity, who generate their own power and invest in new generation.

We use only trusted, qualified and insured subcontractors for anything that doesn’t fall under the broad umbrella of ‘carpentry and joinery’. For example, gas & plumbing, electrics, roofing, plastering, decorating, bricklaying & groundworks.

We can do pretty much anything you, or your architect can think of. All standard areas of carpentry and joinery are covered. It’s not an exhaustive list, but think interior alterations, loft extensions, bedroom wardrobes, kitchen fitting, bathroom fitting, door hanging, window fitting, flooring, fitted and bespoke storage (ie alcove storage), cladding, soundproofing, garden structures, skirting and architraves, loft conversions, home office, exterior repairs and many more. We also have extensive experience of unusual and challenging bespoke work, usually through architects but also designed by me.

If you hire us, you get me. We only take on one project at a time. I oversee and check all work, as well as still doing a lot of the work myself.

We work cleanly and efficiently, using M-class dust extraction and appropriate protection measures for your property. We have a 'zipwall' temporary walling system for isolating parts of a house during larger, dirtier works. Even smaller works are planned and designed to minimize disruption and time at your property.

Core Services:

Low-Carbon Retrofit

We can upgrade the energy efficiency of your home or office to the highest standards. Wherever possible we use sustainable, non-toxic materials such as wood fibre insulation. Insulation projects often fail because the interfaces between materials, construction types or even processes are weak. In consultation with your Architect or Retrofit Designer, we make sure these crucial details are addressed, to reduce or eliminate thermal bypass and thermal bridges.

Insulation, draught proofing and all ancillary works are currently rated at 0% VAT. For example, if we install underfloor insulation but your floor is in substantial need of repair, those repairs are also rated at 0% VAT. Likewise with wall insulation - all works to fascias, guttering, rendering are covered by the reduced rate.

Fine Carpentry

This is our core trade and we are proud of our exacting standards. Structural, First Fix, Second fix, joinery and cabinetry. We use the best quality tools available combined with many years of experience to give you the best possible results.


We undertake domestic alterations, extensions and new-build work, usually in the Primary Contractor role. We don't do our own designs, because there is a longstanding system of separating the designer & contractor, and this system works well. We can recommend some of our favoured architects & engineers to progress your project.


We're always looking for skilled carpenters, general builders and apprentices.

Problem solvers, environmentalists and detail-obsessives welcome.

Send your CV and a cover letter to info@parnosa.co.uk