single family residence, slab repair 9owner neglect0

huangyhg

single family residence, slab repair (owner neglect?)
i live in dallas tx and our house is a brick exterior with a slab foundation 1800 sq ft 1story.  two years ago i noticed a hairline crack running vertically up transverse exterior brick walls at either end of the house,  additionally there were cracks coming out of the door corners on the south side of the house along transverse interior walls.    well,  just recently i noticed that the cracks in the corners of the doors have started to get bigger  and found that i could stick a key (1/4" wide ) through the crack in the exterior walls at either end of the house ( starting  about three feet down from the roof).  additionally there are now cracks at every door along transverse walls (north & south sides) with cracks in the vertical direction in the middle of the door (buckling?). however all doors still closed and latch.     
i called a foundation repair company  and they are coming out next week for an estimate.  i have a couple questions before they get here.  
1)  should i have reacted to this when i first seen these cracks?  my wife bought the house before we met &  i guess  (after recently looking at the initial inspection report when  refinancing) there was a note by the house inspector that there were typical cracks in the house,  but they would need to be evaluated by a structural engineer if requested (it was not requested).  i just moved to this area three years ago and have never dealt with foundation problems before, so i was just ignorant to the matter.
   
2)  from what it looks to me,  the slab has cracked the length of the house (east to west),  and now the north and south side are separating. if they give me options for repairs,  what is the best method (cost effective & resale value)? or if there is usually just one repair method, does anyone know how much this usually cost for this size house?
thanks for the help,
scott
scott
how old is the house?
any previous history of movement or repairs?
can you see any similar distress in neighbouring properties?
have the neighbouring properties been built by the same builder to teh same design?
are there any large trees close by?
what is teh soil - sndy or clay ?
have you had a lot of rain or drought these recent years?
such background info will assist with proposing suitable questions for your contractor next week.
jeg,
how old is the house? 1982
any previous history of movement or repairs? not to my knowledge
can you see any similar distress in neighbouring properties? yes
have the neighbouring properties been built by the same builder to teh same design? yes
are there any large trees close by? yes
what is teh soil - sndy or clay ? sand top with a clay base
have you had a lot of rain or drought these recent years? wet spring with dry summer
i don't know enough to be really helpful.  what i do know is the dallas/fort worth area is notorious for swelling clays.  put that together with home builders being notorious for not accounting for soil conditions and you might have slab problems.  my question is why it took twenty years to develop?
i'd check with your neighbors.  likely they've had similar problems and could give you advice on repairs.
is your huose insured? if yes put in a repair claim.the rest of the business of catching anybody liable for damages shall be follwed out by the assessors.
9scott
when clay enters the picture and neighbouring properties have similar problems,you need detailed advice from local experts.
oijammu and jedclampett have already provided sound basic advice.
when talking with the repair company you should ask how long they guarantee their work and how is the guarantee supported - bank or insurance company bond.
good luck