In English we look at things differently, especially if you consider modern architecture (American/colonial style houses with no gables, buildings with flat roofs).

Traditionally buildings tended to be rectangular, with short gable walls (triangular at the top, no gutters) and long side walls below roof gutters.

These days, a lot of houses (in the US/colonial style) do not have gables, hence all the walls have gutters at the top. They would therefore all be murs gouttereau.

Which means that since we cannot distinguish walls by referring to gables, we have to find another means, and the answer is simply geometrical: we have side walls and end walls.

Note the definition of 'gable, gable end' in the Penguin Dict of Bldg: "The triangular part of the end wall of a building with a pitched roof between the barge boards or rafters...".

Note also, however, that it would be possible to have a building where the long walls have gables and the short walls carry gutters, so the above use of 'end wall' would not work.

In general, though, buildings of simple geometry (and not square or circular), you'll have end walls (mur pignon) and side walls (mur gouttereau).

The Forbes Dictionary of Architecture and Construction gives mur gouttereau as 'eaves wall' (never 'eave' without an s) but I suspect this is an invention for the needs of translation, when, by my books at least, the translation has to be adapted to actual English conditions.



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Note added at 1 hr (2023-10-12 09:22:11 GMT)
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Note added at 2 hrs (2023-10-12 09:42:07 GMT)
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This does not preclude referring to the gable aspect of a wall if there are gables, but I'd add 'end', so you'd have 'gable end walls' (or just 'gable ends') and 'side walls'.

gable end in British English noun. the end wall of a building on the side which is topped by a gable.
https://www.collinsdictionary.com/dictionary/english/gable-e...


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Note added at 2 hrs (2023-10-12 09:42:44 GMT)
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Note added at 6 hrs (2023-10-12 13:37:08 GMT)
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Wow! I've just looked into my archives and found this exchange, from 2005, with a colleague asking about the meaning of "end flank wall":

Question: Bracing to the retail pavillion is provided by the end flank walls
end walls ? flank walls ? (et en passant : end wall : mur pignon et flank wall = gouttereau ??)

My answer:
Scott donne:
flank wall, side wall = A wall at one side of a building, not a front or back wall. Je dirai donc pignon, terme qui s'emploie pour des murs autres qu'à V inversé de nos jours: un bâtiment à toit-terrasse a 4 murs gouttereau(x?), dont 2 façades (avant et arrière) (murs longs en général?) et 2 pignons (murs courts en général?). On précise "end flank wall" pour distinguer entre un bâtiment "A4" "à l'italienne", avec façade longue sur rue et deux pignons (end walls, mais aux "sides"), et un bâtiment "à la française" avec façade courte (pignon sur rue) et deux murs latéraux longs (flank wall plutôt que "end wall"). Bref, compliqué.