With concrete and slate sills the exposure to the variations in temperature can cause cracks and crumbling water penetration can also weaken the joints.
Repair cracked concrete window sill.
Stone windowsills add old world charm to many buildings.
Rub off flaking paint or loose concrete along the crack with the wire brush and make sure to clean out any moss that may be growing inside.
Worn or loose joints.
To avoid this check regularly for.
As this may.
Resurface stained or cracked concrete window sills with new concrete.
Repairing a woden sill.
How to repair sandstone window sills.
Puddles of water collecting on the window sill.
Cracked or worn paintwork.
If sills are sandstone the stone tends to deteriorate with age exposure to rain snow and freeze.
Apply a 3 8 inch thick layer of concrete all over the sill with a trowel following any contours to mimic its original shape.