The most common and most likely answer to this crossword clue is the 10 letter word SANDCASTLE
I've seen this crossword clue in Financial Times
S
A
N
D
C
A
S
T
L
E
More clues leading to the result SANDCASTLE
- Alec stands waving something on the beach
- Temporary structure built on The Strand?
- Last dances arranged in temporary beach construction
- Keep expecting to get lost in the main
- Building ascends at last in Bristol, temporary construction
- Polish company backed extension to building, one that goes with the flow?
- 10’s workof George who wrote Kafka’s
- Strand building shortly due for demolition?
- Too bad about knight; rook, keep at the front
- Keep close to the sea’s edge?
Buddy explains!

The straight part
We know that "Temporary structure built on The Strand" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case temporary structure built on the strand = sandcastle.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SANDCASTLE mean?
SANDCASTLE noun- A sculpture made of sand and resembling a miniature castle; typically, but not always, made for fun by a child on a beach.