Garage door conversions
Structural Calculations for Garage Door Conversions
Order online · Building control ready · Worked remotely · You choose the date
Replacing your garage door with a window, a standard door, or a solid wall is one of the simplest ways to reclaim the space — but the opening still needs a properly designed lintel or beam, and building control will ask for the calculations to prove it. Calcs-Online provides exactly that: a structural calculation pack you can order online. Pick when you need it, see its price, and add it to your basket.
- 9,000+ Projects Since 2012
- 100% Approval Rate on Our Calculations
- Structural engineers
- Priced by the date you pick
One opening: new lintel, infill wall, and window — all designed and checked
Your garage door calculations
One opening, designed properly.
Order online
The price covers the complete structural design for the new opening, and the date you choose sets it. Add it to your basket and order online.
Lintel and beam design
We size the lintel or beam over the former door opening, calculate the wall loading above it, and confirm the surrounding brickwork can carry the new arrangement.
Approved, or refunded
100% building regulations approval rate across 9,000+ projects since 2012, with a free refund if your calculations are ever not approved. The pack is prepared for what building control asks to see.
100% Building Regulations Approval Rate For Our Structural Calculations
What every quote includes
- Want an engineer to look first? Get in touch.
- Up to £500,000 insurance
- Money back if our calculations are not approved
- You choose the date; each date shows its price
- Worked by structural engineers
- A clear price, and a date you choose
What do garage door conversion structural calculations include?
A garage door conversion replaces the door opening with a window, a standard door, or a solid wall. Structurally, every version asks the same question: what holds up the wall above the opening? Your calculation pack answers it in full:
- Lintel and beam sizing for the new opening
- Wall loading calculations above the new opening
- Structural adequacy of the surrounding brickwork
- Compliance documentation for building control
- Contractor pack with clear instructions for whoever builds it
Three ways to close the opening — all covered
Window + wall: the most popular option — brickwork below a new window keeps light in the room while closing the opening.
New door or French doors: keep access with a standard door, French doors, or a door-and-window combination.
Brick it up entirely: a full infill wall for storage, utility, or workshop use.
Whichever you choose, the lintel design accounts for the full width of the original opening, so any arrangement is covered by the same price; the date you choose sets it.
Converting the whole garage into a room?
A full garage conversion — bedroom, office, or living room — involves the floor slab, walls, and roof as well as the openings. That’s a separate service with its own pricing, quoted individually for your project.
Garage conversion structural calculations →Why choose Calcs-Online for your garage door conversion?
Order online
Pick a date, see its price and check out. Then send us photos and the dimensions of the opening.
Building control ready
Calculations prepared specifically to meet UK building regulations, backed by a 100% approval rate and a free refund if they are ever not approved.
Worked remotely
We work from your photos and measurements, anywhere in the UK.
A date that suits you
You choose when you need your calculations; each date shows its own price.
Talk to an engineer first
If you would like an engineer to look at your photos and dimensions before you order, get in touch.
Structural engineers
Every calculation pack is produced by our structural engineers: the team behind PorthouseDean, 9,000+ projects since 2012.
Common garage door conversion questions — solved
What happens to the garage door opening?
We design the lintel or beam for the new opening and specify the wall construction above it — whether you’re fitting a window, a standard door, or bricking it up entirely. Building control will want to see exactly this, and it’s the core of your pack.
Is the surrounding brickwork strong enough?
Single-skin, cavity and blockwork walls all behave differently around a modified opening. We check the brickwork either side of and above the opening, and specify strengthening only where it is needed.
Does the new infill wall need its own foundation?
Sometimes: it depends on your slab and the weight of the new wall. We specify how the infill wall is supported, on the existing slab, a thickened section or a new strip footing, so nothing is left to guesswork on site.
Do I need building regulations approval for this?
Yes. Replacing a garage door with a wall or window is a structural alteration, and building control will expect calculations for the new opening. Planning permission, on the other hand, is rarely needed — most door conversions fall under permitted development.
Can I fit both a window and a door in the same opening?
Almost always, yes. The lintel design accounts for the full width of the original opening, so how you divide it up underneath — window, door, or both — is largely a design choice. We cover any arrangement at the same price.
How it works
Choose your date and add to basket
Pick when you need it and check out online; each date shows its price.
Send your project details
After checkout we’ll ask for clear photos of the opening inside and out, the opening dimensions, and what you’re replacing the door with. No architectural drawings required for most door conversions.
Structural design
Our engineers size the lintel or beam, check the wall loading above the opening, and confirm the surrounding structure is adequate.
Calculations delivered
Your full calculation pack arrives on the date you chose, building control ready, with a contractor pack to build from.
Support to sign-off
Questions about the calculations from building control or the builder come to us until the work is approved.
Choose when you need it
Same calculation pack, same engineers: you choose when you need it, and each option shows its price.
Secure checkout. After you order, we will ask for photos and dimensions of the opening, and we begin once we have everything we need.
Get the structure right before work starts
Structural mistakes are expensive: work ripped out, repairs nobody budgeted for, an application refused.
Calculations checked before the build starts take those risks out. Building control sees what it needs, and whoever builds it knows exactly what to fit.
Calcs-Online works from your drawings and photos. Want an engineer to look first? Get in touch.
Talk to an engineer first
If you would like an engineer to look at your drawings and photos before you order, get in touch.
Worked from your drawings
Calcs-Online works from the plans and photos you send, and the calculations come back ready for building control.
Approved,
or refunded
Our structural calculations have a 100% approval rate across 9,000+ projects since 2012, and a free refund if yours are not approved.
“They asked good and very detailed questions of us and were very patient in dealing with our queries Lack of use of any jargon made things very understandable for us.”
FAQ
Questions
Do I need structural calculations to replace a garage door with a wall or window?
Yes. The opening needs a properly designed lintel or beam, and the wall above it must be shown to be adequately supported. Building control will ask for these calculations before signing the work off.
What does it cost?
Each option in the picker above shows its price, including VAT, before you pay. Garage door conversions are a well-defined scope, which is why you can order online. If you would like an engineer to look at it first, get in touch.
What do I need to provide?
Clear photos of the garage door opening inside and out, the width and height of the opening, and what you plan to replace the door with. If you have drawings, great — but they’re not essential for a door conversion.
When do I get my calculations?
On the date you choose when you order; each date shows its price. We start once we have the photos and dimensions of the opening.
Will my calculations pass building control?
Yes: a 100% approval rate on 9,000+ projects since 2012. If yours were refused, you would get a refund.
Sort the structure before the build starts
Garage door conversion structural calculations: order online, building control ready. Choose when you need it and add it to your basket.
