Before choosing all the nice things for your Refurbishment we always suggest to plan your first fit refurbishment first. By first fit we mean the structure of the house and things which go before decoration, such as damp proofing, plumbing, electrical, etc. So what is important to check before starting a refurbishment.

Structural Movement.

If you can feel or see that walls or floor is not totally square or straight that might mean that the building may have suffered structural movement. Cracks on the walls, especially around windows and doorways can help identify the movement. The building can move because of the failure of structural elements or due to movement in the ground. Period houses which experienced movement can be repaired by the team of professional builders. 
The important thing is to find out whether the movement is historical, sleeping or active. Historical movement can been corrected with metal ties, underpinning, piers, metal staples and stitching and buttresses, all of which can add to the character of an old house. 
Active movement is the one to be most unpleasant one. If you noticed some new visible cracks or failed structural elements, with signs of fresh dust, that could be a sign of structure movement.  The structure will have to be stabilised, possibly by underpinning or soil grouting, and then repaired. The work involved can be substantial and you should not proceed without specialist advice.

Original Construction.

Understanding materials and methods used in the construction  can help to calculate refurbishment costs. Houses built after World War I may have cavities and these can often be insulated for very little cost. Older houses are likely to have solid walls, built using lime mortar rather than cement, and so any repairs need to be on a like-for-like basis. In those types of houses insulation will need to be added on the internal face of the walls, but walls will need to stay breathable to prevent damp problems.
Some of the old constructions may not have a good foundation. This will need to be taken into account when designing an extension or additional levels to make sure that new alterations will not destroy the original construction. 

Damp-proofing
Damp in house could be noticed by smell first. Mould and fungi are usually present, rapidly creating a musty or mushroom smell. You can also spot damp because of either the presence of water, damp patches, mould, wet or dry rot, white salt deposits on brick or stonework, and/or failing plasterwork on walls and ceilings. It is very important to detect the damp as early as possible, "destroy" it and do some damp proofing works.

Plumbing.

If you are changing, relocating or adding bathrooms it is worth considering replacing the plumbing system. If you are going to be lifting floorboards anyway in order to rewire, or making other alterations, adding new plumbing, waste and soil pipes will be worthwhile. 

Heating System.

If there is a central heating system, find out what fuel it uses and the age of the boiler. Your contractor can suggest if existing boiler is in a good condition or need replacement. 

These are only part of the points we suggest to check before going ahead with the refurbishment. A professional team of designers/architects and builders can help you to check condition of your house and advice on works, which are needed to be done.