It is the dream of every child to have their own personal space. You should respect this and let your child have it. Their room is not enough given that it is just in the house. To motivate your children to be active outdoors, you can build them a treehouse. Thus, if you decide to give them a treehouse you should make sure you do it right. There are professionals treehouse builders you can approach for this task. Poorly built tree houses will be a safety hazard and you should not put your kids to a situation where they will likely be injured. You ought to have the traits of great treehouse house at your fingertips when interviewing the person you want to take up the job.
In order for the project to be a success, you need a person who is great at building, supporting and planning. You should also hire someone who has a long list of satisfied clients. It is not weird to feel like something is wrong with a particular builder even when there is nothing tangible to support this. It is true that you may have done your research and found that everything looks great on paper but this should not make you ignore your gut feeling. It might be for good or bad but it is better to make changes early than regret later about why you did not listen not what your gut was telling you.
Find a builder who brings more to the table than just the skills but also input on the designs you should take into consider. Given that they have been doing this for a while, it means that they will have information on the best stores you should shop at for the best building materials. You will be entering into a working relationship with the builder and it will be bad for everyone if the two of you cannot work together well because at the end of the day disagreements are going to hurt you. There is no standards price when it comes to building a treehouse and you have to negotiate the cost with the builder before you sign the contract so that you can determine whether you can raise the money or not given that paying more for the treehouse than you did for your main house is not a wise financial move.