Bright space, low maintenance, year-round comfort.
uPVC conservatories give you a brighter room with frames that are easy to look after. Pair modern profiles with the right roof and glazing and you get a space that feels comfortable in winter and calm in summer.
We design, supply and fit across Grantham, Stamford, Sleaford, Newark, Bourne, Melton Mowbray and nearby villages.
Low maintenance
No repainting. A simple wipe keeps frames looking smart.
Warm and quiet
Insulated roofs and high performance glazing help control temperature and noise.
Great value
Strong performance and good looks without a premium price tag.
Styles for every home
From simple lean-to footprints to statement Victorian or P-shapes.
Flexible upgrades
Choose performance glass, hybrid or solid roofs, lanterns and neat interior finishes.
Use these as cards that click through to child pages or anchor sections.
Lean-to
Clean, simple lines that suit bungalows and tight spaces.
Edwardian
Square footprint with a pitched roof. Easy to furnish and bright.
Victorian
Gently faceted front for a softer look from the garden.
P-shape / L-shape
Combine zones for dining, seating or play without losing flow.
Orangery-style uPVC
uPVC frames under a perimeter roof with a central lantern for a real room feel.
Roof upgrades
Hybrid and solid roof options available if you want more insulation with targeted daylight.
• Smooth finishes in white, cream, anthracite and black • Timber-look foils for period properties • Dual colour inside and out to match décor
• High performance double glazing as standard • Solar control to cut summer heat and glare • Self-clean coatings for easier upkeep • Acoustic or laminated glass near roads and schools • Privacy options for side elevations
• Aluminium bi-folds for a wide opening • Sliding doors for the most glass • French doors for classic symmetry • Trickle vents and secure night-vent positions where required
A comfortable room starts with the roof. We will recommend the right option for your aspect and usage.
Keeps things light with coatings that reflect unwanted heat and insulate in winter. Self-clean and warm-edge tech reduce maintenance and condensation.
Mix insulated panels with glass where you want daylight. Great for south and west facing gardens.
Plastered interior with a tiled exterior to match the house. Quiet, private and warm with the option of roof lights or a lantern.
Bring daylight into the centre without harsh side glare.
Insulated roofs, low-e glass and warm-edge spacers help achieve low U-values, so the space is usable in winter without a portable heater.
Glass options that reduce heat gain and glare while keeping daylight.
Layered structures and laminated options soften rain and outside noise for calmer conversations.
Better glass edges and ventilation planning reduce misting and damp sills.
We visit, measure properly, look at your existing frames and talk through finishes, glazing and hardware. It’s a conversation, not a sales pitch.
You’ll get an itemised quote with the style, colour, glass spec, lead time and warranty. No vague “from…” pricing and no surprises later.
Every frame is built for your apertures. This is what keeps the installation neat and the seals tight.
We protect floors, remove old frames and glass, seal up neatly and clean down. Old materials are taken away. You’re not left with a skip.
If you ever need us, you don’t get pushed to a call centre. You speak to the same team who fitted the job.
We measure properly, check structure and talk through shapes, roofs, doors, colours and finishes. It is a conversation, not a pitch.
Clear plan and elevation, specification, timelines and warranties. Any groundworks or approvals are listed.
Frames, roof and glass built for your sizes so sight lines are neat and seals are consistent.
Floors protected, structure assembled, roof set, edges sealed and trims finished cleanly. Waste removed.
If you need us, you speak to the same friendly team who built it.
Serving Grantham, Stamford, Sleaford, Newark, Bourne, Melton Mowbray and nearby villages.








Many uPVC conservatories fall under permitted development if size and position limits are met. Conservation areas and certain house types can vary. We will confirm what applies to your home before you commit.
With the right solar control glass it stays bright without the greenhouse feel. Hybrid and solid roofs add even more control. We will recommend the right spec for your aspect.
Often yes. A roof replacement with performance glass or a solid or hybrid roof makes the biggest difference. We will assess frames and foundations first.
With an insulated roof system and high performance glazing you should expect comfortable winter use. We will discuss realistic U-values and heating options.
Yes. We can include lighting, sockets and plastering in the quote or coordinate with your trades. Everything is itemised.
A new uPVC conservatory varies with groundworks and size. A straightforward roof replacement is often two to three days. You will get a realistic schedule with your quote.
White, cream, anthracite and black are popular. Timber-look foils such as oak, rosewood and heritage creams are available. Dual colour is an option on many systems.
Yes. We take away old frames, roof panels and packaging and leave the area tidy.
Trustindex verifies that the original source of the review is Google. I have been using Avanti for 35 years and the service and product quality is amazing!Posted on Google Will mcintoshTrustindex verifies that the original source of the review is Google. Cannot recommend Avanti enough!! Amazing service from start to finish. The whole team were friendly and professional. Great job and have told all my family and friends if they ever need a job doing, to give them a callPosted on Google Natalie BuxtonTrustindex verifies that the original source of the review is Google. We had nine blown windows, called a couple of window companies to try and get the best price and these guys were the only ones who got back in touch with us. We weren't willing to wait around so went with them and I'm glad we did. They came out, took the measurements and ordered the glass. I was advised the glass could take about four weeks which was fine. Less than a week later I got a call asking if there was any chance they could come later today to fit our new windows! They came round and had them all replaced in about an hour!! For the first time since we've moved into our house we have been able to see properly out of our window! Thank you for the professional and prompt service! I would recommend.Posted on Google Lisa KnightTrustindex verifies that the original source of the review is Google. We have this week had our windows installed courtesy of Avanti Windows Grantham. From start to finish we have had excellent service. I knew I was in safe hands when I met Richard who came out originally to measure up and quote, but to be honest everyone we have dealt with from Richard through to the fitting team have been spot on. Very professional. We did get quotes from other well known window suppliers but the out dated sales tactics and tedious process put us off. There was none of that with Avanti…. It was so easy. I would highly recommend them. I’d give 6 stars if I could👍🙏Posted on Google MARK GOODETrustindex verifies that the original source of the review is Google. Amazing firm and very professional. They’ve done a great job In replacing our conservatory roof for a solid one. Punctual everyday and end result it brilliant. Highly recommendPosted on Google George PimTrustindex verifies that the original source of the review is Google. Avanti delivers an outstanding service. I had a new glass roof fitted on my conservatory and the team also refurbished the whole conservatory and made it look like it was new. Fantastic job, exceeded my expectations. I have no hesitation in strongly recommending this company. A big thank you to the whole team at Avanti, a great bunch of guys!Posted on Google Douglas HowcroftTrustindex verifies that the original source of the review is Google. Brilliant company. Quality windows. Staff really friendly and helpful.Posted on Google Chris JonesTrustindex verifies that the original source of the review is Google. Absolutely over the moon with my windows and doors, service and fitting is top notch!! We will be having replacement windows from them in the future!!Posted on Google Toni BlakeyTrustindex verifies that the original source of the review is Google. A patio door leaked because they "forgot to put in drain holes". Ahe door got fitted by "trimming" the opening by wacking it with a lump hammer (even though the builder was on hand with a diamond saw), the windows came scratched and the external paint could be removed with a finger. I saw they hadn't sealed in the window frames and asked why not. Apparently they don't carry sealant!?!? They all got taken out and my builder rebuilt the door opening.Posted on Google Sheila and PeterTrustindex verifies that the original source of the review is Google. Tony and the team were very professional throughout the whole process. The fitters had to install all new windows and doors and have completed to a high standard. They have been very accommodating with my timescales and would highly recommend. Thank you!Posted on Google Evie English