plan_maison_hatch.dxfI cleaned up your roof during by removing gaps between entities of the contour:
1, Modify->Move to move one entity (let's call it entity A, from now on) of the contour by offset 100,0
2, check "Snap to endpoints" only in the "Snap toolbar"
3, select a neighbour of the moved entity A in step 1 by selecting the connection point of this neighbour as reference point, and the the connection point of entity A as the target point; select "Delete existing" to continue;
4, repeat step 3 for all entities left in the contour by the contour order
5, After the last entity moved to new position, use Modify->"trim two" to close the potential gap to entity A;
6, move the contour back by offset -100,0