Summer seems a long way off as we battle ice and snow, but start planning now, and you’ll be all set for warmer weather when it arrives.

If there’s one way to let in the sunshine and light, and make a room look amazing, it’s installing bi-fold patio doors.

Unlike French windows or sliding patio doors, bi-fold doors consist of three or more doors that fold back on themselves and sit flat against one wall or both walls, depending if they open in the middle or at the side.

It’s a case of the bigger, the better, because bi-fold doors look most impressive when they span a whole wall.

When the weather’s nice, you can fold them back to open up the wall for a fabulous indoors-outdoors room.

If you want to turn your living room or kitchen-diner into a stunning entertaining space, bi-fold doors are just the thing.

These doors are most effective when the floor levels on both sides of them are the same. This may involve some work in the garden, but it will improve the indoor-outdoor flow and increase the wow factor, especially if you lay similar or the same flooring inside and out, such as decking and wooden flooring.

You can get standard-sized bi-fold doors from DIY stores (starting at around £1,000), or standard-sized or bespoke ones from window and door companies.

Bespoke doors generally cost more, but the company will (usually) install them and provide a guarantee.

Obviously, the bigger the opening, the more doors you’ll need, which will increase the cost. And it can be more complicated than just fitting the doors, as you may have to replaster, redecorate and move things such as radiators, pipes and wires.

It’s not usually necessary to get planning permission to fit bi-fold doors, but there are exceptions, including homes on ‘designated land’, such as conservation areas and areas of outstanding natural beauty, and listed buildings.

If you live in one of these, you’ll need listed building consent from your local council’s conservation officer.

To check if you need planning permission, ask the council’s planning department. As with any alterations, if you live in a leasehold flat or house, you may need the freeholder’s permission to add the doors.

If you fit the doors yourself, or get a builder to do it, the council’s building control department will need to check and sign off the work to ensure it complies with building regulations, for which it will charge a set fee.

The easier option is to use a window and door company that can self-certify that its work complies with building regulations, such as companies belonging to FENSA (double glazing).

Either way, you need a certificate to show that the doors comply, otherwise you may have problems when you sell your home.

Unless you have an existing window, doors, or window and door that matches (or is bigger than) the size of the opening required for the bi-fold doors, it will be necessary to fit a steel or concrete lintel above the opening.

Your first step (at the planning stage) should be to get advice from a structural engineer, or, again, use a window and door company to supply and fit the doors.

It should carry out a survey and then do whatever’s necessary to make your home structurally sound.

Product of the week

You won’t get far DIYing without good paintbrushes, and they don’t come much better than Dulux’s. They’re comfortable to hold (even for a long time), quick and easy to clean, and produce a really good finish – the bristles are split to minimise visible brush marks. The bristles are also long and firm, making it easy to do precision work.

The brushes come in two ranges – Perfect Finish ones (from £3.79), which are flat, and Perfect Edges ones (from £4.99), which are triangular and should be held like a pen to give greater control.

The brushes are even designed to be laid flat without the bristles picking up dirt and they have a built-in paint-tin opener, so you don’t have to waste time looking for a screwdriver or chisel – brilliant! For more information, visit www.dulux.co.uk

How-to tip

Extruded polymer (like polystyrene) coving may seem like the poor relation to plaster or resin coving, but once fitted, filled and painted, it looks just like the real thing. Best of all, it’s a lot cheaper and easier to put up – just use grab-and-grip or coving adhesive – and it comes in period (try the Easycove Regency Room Kit, £29.48, B&Q) as well as modern designs. Double-fill the joins with flexible filler or decorator’s caulk, but be careful not to paint emulsion thickly over it, as it will crack.