Assume nothing!
Although you might assume that a contract should look a contract, anything you sign could be used by a contractor as authorization to go forward with your project.
This means that any budget you sign may become the contract.
Do not sign anything until you completely understand what are you signing and agree to all the terms.
Be sure to ask questions until you fully understand the contract and what the work will look like. Before signing anything, you may wish to discuss the proposed contract, plan and specifications with your solicitor.
Have it in writing!
The contract binds you and the contractor to the project. Since a written contract protects both parts, all agreements should be put in writing.
It should include everything you have agree upon and the extent of the work to be done.
Get all oral promises in written and spell out exactly what the contractor will and will not do. If you intend to do some of the work yourself or hire another contractor to do it, this also should be written into the contract.
Never sign a blank or partially blank contract. Currently you sign two sets of contracts, sign both in every page, as the contractor has to do, and keep your set for your records.
Both you and the contractor are bound by everything set down in the contract, so read it carefully before you sign.
If you have any questions or don´t understand something, ask before you sign.

The contract should include the total price, when payments will be made and weather there is a cancellation penalty. On any home improvement work you should expect to make a down payment. Currently and obviously depending the work, 10% of the contract price is asking for the builder.
After you have a signed contract, and even after work has already begun, your contractor may offer suggestions that will change your original ideas for the work.
The contractor should clearly state your final agreement and accurately reflect everything involved in the work being done by your contractor.
If you have discussed added work, substitutions of materials or equipment, or changes on the completion date, make sure that clearly worded and signed “change orders” reflect this.

Disclaimer: Daniel González Aranda through Survey Andalucía, assumes no responsibility for any damage that arises from any action that is based on these articles.
Questions regarding civil law, insurances policies should be addressed to a solicitor.
For a free consultation regarding technical questions or any other matter in relation with the published articles you can call at 686 846 624 or e-mail to surveyandalucia@gmail.com