Now is common that people has their house renovated. It mainly carried out after house owner has obtained approval from relevant approval agency. Normally we will not know when house defect will be happened. Most of the defects will happen after certain period of time. But it may have sign of immediate effect. Immediate house defects shown mainly due to very poor qualities of workman ship, poor material used, building structure is under designed and ground condition. There are a number of possibilities of house defects will happen. It will depend on case by case basis.
One of the common defects that are the cracks line will be appeared along the joint between new building and existing building. If the building foundation is pile foundation then the effect of cracks will be more significant. It is because most of the extension works that carried out by renovation contractor is using pad foundation. If existing building is pile foundation and new extended building is pad foundation; then there will be significant of differential ground settlement. This differential settlement will make cracks happened.
It is happened because a lot of people who want to renovate house will look for building contractor, but they have forgotten that they need to look for engineer first before engage a building contractor. Un-reputable contractor will not help house’s owner to engage a structural engineer, contractor will build the house based on his owner experience. Furthermore; he only expertise on builder works, he does not has expertise on ground investigation, theory of structure and design of structure. As a result, the finish product will cause the cracks line happen as mention above.