There is 2 type of Interior design. One is the 3D art/rendering and the simple layout. There is not included detail of the construction method and materials such as important preparatory work / spadework before the surface work. In this case, the quality and durability of the construction will be committed by the skill and knowledge of the renovation contractor.
And, It won’t become cost downand it will be additional cost. The interior design fee is included to the renovation cost even if it is free of charge.
This type of interior design is the purpose for the customer to imagine the completion of the renovation. Therefore, you can see and check the house design visually before the renovation work. Then, You can avoid the difference in image of housing renovation. But, please note that 3D art/rendering is usually much better than the actual renovation.
Another type of the interior design is the blueprint/drawing and detail of the renovation work with quantity survey. Therefore, the quantity of material can be calculated accurately, the cost will be lower very much. Because it is not a calculation in bulk/lump-sum. The renovation contractors do not need add up the extra costs such as the buffer for the unexpected work.
And, the detailed blueprints/drawings will be the working instructions to the renovation contractor. Therefore, the quality and durability of the construction will be much better. The detailed blueprints/drawings will be one of the agreements with the renovation contractor. It will be a clear breach of contract, if the renovation contractor did the shoddy construction.
The interior design with the detailed blueprints/drawings makes high quality, high durability and the cost savings. However, if the renovation is too small project, the quality and durability is much better, but the total cost will be high. Please discuss with a renovation contractor with knowledge.
And, please note that it won’t be a cost savings in the case of the renovation contractor to calculate by lump-sum even if there is blueprint/drawing. It is important that you ask the renovation contractor who can understand the blueprint/drawing and the quantity survey. If you ask the renovation contractor who do not have knowledge enough, the interior design with the detailed blueprint/drawing will be wasted.