Which gutter profile do I need?

How do I tell which profile is already on the house?

Look at the open end of a run from the ground, through binoculars or a phone camera zoomed in. The stop end shows the section shape better than anything else.

Half round is a plain semicircle. Deepflow looks like a half round stretched deeper with a squarer base. Ogee has a flat back and a stepped, moulded front; it is the plastic version of the cast iron ogee on Victorian and Edwardian houses. Squareline is a rectangle, flat front, flat bottom. Do not climb up to check. Photograph it from the ground and bring the photo to the counter, or send it to us.

What is the difference between the four?

Profile	Size	Section shape	Capacity against 112mm half round	Usually found on
Half Round	112mm	Semicircular	Baseline	Most post-war housing and new build
Deepflow	120mm	Deep, squared base	Highest of the four	Large or steep roofs, long runs to one outlet
Ogee	125mm	Flat back, moulded front	Above half round	Period-look houses, cast iron replacement
Squareline	112mm	Square, flat front and base	Similar to half round	1980s to 2000s estates

Gutter lengths are 4m in every profile. Brackets, unions, stop ends and outlets are profile-specific and priced separately, so cost a whole run rather than comparing one length against another.

Which profile carries the most water?

Deepflow 120mm carries the most of the four. 112mm half round carries the least. Ogee 125mm sits between them.

Capacity comes from the cross-sectional area of the channel, which is why the deeper sections win. A 112mm half round handles the roof of an average semi without trouble. Move up to deepflow or ogee for a large roof, a steep pitch that dumps water fast, or a long run served by a single outlet. Be honest about the diagnosis first: a gutter that overtops in heavy rain is usually blocked or wrongly fallen, not undersized. Check the fall and clear the run before buying a bigger profile. For an actual calculation, ring us with the roof dimensions and the pitch.

Do the profiles connect to each other?

No. Half Round, Deepflow, Ogee and Squareline do not join, and their brackets, unions, outlets and stop ends are not interchangeable.

Each profile is a sealed section, and a union is moulded to one shape only. Even where the figures match, the shapes do not. Half round and squareline both quote 112mm and share nothing. The one exception on the shelf is a Squareline to half round adaptor, for the joint where an extension in one profile meets the original house in the other. Anything beyond that means changing the whole run.

Which downpipe goes with which gutter?

68mm round pipe suits half round, deepflow and ogee outlets. Squareline uses its own square downpipe, sockets and clips.

The outlet decides the pipe, not the gutter. If you are changing profile at first-floor level but keeping the existing lower pipework, a square to round adaptor in 68mm makes the transition. Clip spacing is the same either way: 1.8m maximum, plus a clip at every socket.

What if only part of the run needs replacing?

Match the existing profile if the rest of the run stays. Replace the whole run if you cannot identify or source it.

Bring a stop end or an offcut to the counter. Matching from a photograph is guesswork; matching against a physical piece is not. Allow for colour as well as shape, because twenty-year-old white does not sit next to new white without showing. If the run is 1970s or older and nothing on the shelf matches, replacing that whole elevation in one profile usually costs less than chasing discontinued fittings.

Does it matter what the neighbours have?

On a detached or semi-detached house, no. On a listed building or in a conservation area, it can decide whether uPVC is permitted at all.

Terraces are the exception, because the gutter often runs continuously across the party line. Changing your section mid-terrace means someone has to make a transition at the boundary, so speak to the neighbour before you order. For listed buildings and conservation areas, ring the council’s planning department first. Black ogee is the usual compromise where cast iron is not insisted on, but that is the council’s decision, not ours.