Yes, and with less interference than almost anywhere else in Dorset. There are 9 listed buildings in the whole area. There is 1 conservation area, and it sits out on the parish edge. Most of the town went up after the war and nobody has since decided it needs saving from itself. The thing that will complicate your extension here is not the planning officer, it is what is underneath the lawn.
Take the listed buildings first, because the number is the whole point. Nine, across the entire area. None at grade one, 2 at grade two star, and 7 at grade two. Listing applies to the whole building, inside and out, and any alteration needs listed building consent on top of ordinary planning permission, which turns a straightforward rear extension into a negotiation with a conservation officer over window reveals. If you are buying one of the nine you will know, because the estate agent will have used the word "character" a great deal. Everybody else can ignore this paragraph entirely.
There is a single conservation area, at Hampreston, one of the old settlements the parish was named after before it renamed itself. Conservation area designation brings extra consent requirements: permitted development rights can be restricted, demolition needs consent, and work to trees requires notice to the council. It covers a hamlet rather than the town, so for the overwhelming majority of Ferndown addresses it is somebody else's constraint.
There are 10 scheduled monuments in the area, mostly burial mounds sitting on the heaths, commons and one golf course around the edges of the built-up part. Scheduling is the strictest protection tier in the system, and it is essentially absolute: it matters only if your land contains or abuts one, in which case the people buried there several thousand years ago outrank your orangery.
The evidence that people do alter homes here is substantial and current. The planning register recorded 2,658 applications across the area between April 2024 and July 2026, with 1,102 of those in the last twelve months. That is a town continuously converting garages, filling in side returns and building the second bathroom that the original layout never anticipated. Ferndown is not a place where the neighbours object on principle. Most of them are mid-project themselves.
The real constraint is geological. The national geological survey's shrink-swell hazard classification puts this area at class three, its moderate-to-significant band, across roughly 81% of the place. Shrink-swell ground moves seasonally as clay takes on and gives up water, which is a foundation-depth question rather than a reason to abandon the plan. In practice it means your builder will be digging deeper than they would on gravel, a structural engineer should be looking at anything with a mature tree near it, and the quote you got over the phone before anyone opened a trial hole was fiction. Budget for it at the design stage instead of discovering it at the footings stage.
For most houses here the practical position is straightforward. Unlisted, outside the conservation area, detached or semi-detached with space around it, which is the standard permitted development starting point, with consent required once you go beyond what those rights allow. The only genuinely essential checks are whether your specific plot carries any designation and what the ground survey says. Both are cheap. Neither is optional.
Freedom to alter a home here is middling rather than unrestricted, and the reason is worth understanding: heritage constraints are unusually light, and the clay quietly takes back some of what the planning system gives you.