Never take chances with cracks that leak because these are sometimes serious.
Plaster is cracking around windows and doors.
Larger cracks in your walls however can indicate structural or foundation problems.
Use acrylic latex caulk and put a small bead of caulk along the crack.
Cracks in plaster plaster is a very thin component made of mortar.
It protects the outer wall from rainwater.
Cracks in the walls it s a different story if the cracks are in the walls by the doors and windows and not just in the trim.
Diagonal cracks above window openings and door openings are common structural defects that show signs of movement which will need to be rectified.
In my opinion if the cracks are all internal plaster work etc it is not subsidence it will be the cause of what i have mention above.
Most small cracks in drywall or plaster walls are not serious and are caused by seasonal expansion and contraction of the wood framing in your house over time.
Hairline cracks over doors and windows are likely due to settling.
If drywall or plaster surrounding the crack feels damp you may have a water infiltration issue.
If the cracks are outside though you may just have to inspect the trim around your doors and windows periodically and fill cracks as you find them.
Diagonal cracking above opening.
If you determine there s nothing obstructing the swinging motion of the door it might be a sign of a moderate to severe foundation change often resulting in wall cracks.
Houses of any age move and shift subtly over time and the weakest area in a wall is the most likely to crack.
I hope this has helped answer you question.
There are many types of lintels available and in use such as brick arch and soldier course lintels commonly found in period properties.
It is applied on the surface of masonry of the house to get the smooth decorative surfaces.
Small cracks located above interior windows or doors are usually harmless.
They re often found at the corners of window and door frames and can be patched using spackling or joint compound.
The repeated force of the door closing can eventually cause stress fractures in the surrounding plaster.
Those types of cracks indicate some sort of shift in the house itself.
This will force the caulk into the crack.
Wipe off all the excess with a sponge so that the only caulk left is in the crack.
If it were subsidence you would see cracks in the external masonry more than likely running down the sides of windows and doors and through the masonry between them.
Check whether water is leaking into the crack.
According to msn real.