Choose a qualified expert early in the process, with the involvement of your legal counsel
If you think you have a construction defect or property damage at your home, condominium, or commercial building, It is absolutely critical that you get your expert(s) -- well qualified experts experienced in forensic work -- involved early in the process. But take note: It can be risky to have an expert doing anything on your building without guidance and involvement from an attorney. Experts need to know whether, when, and how much to investigate, and these are all questions that can have different answers depending on the condition of the building, the occupants, the suspected damage, the potential claims, and the likely parties and/or insurance companies who we may be looking to for a remedy. Also, there are many different kinds of experts, and your attorney can help you determine the type of expert you need.
Assemble all of your documents
Construction experts, like attorneys, rely on evidence. For an expert, this can include their observations, the results of their intrusive investigations, moisture testing, and measurements, and of course the construction documents. These documents might include construction contracts, invoices, estimates, purchase and sale agreements, emails, letters, and in the case of condominiums, the Declarations, CC&Rs, and even the Bylaws. Make sure that you have all of the documents together and in a safe place. Err on the side of including everything, and let your attorney figure out what might be relevant.
Don't alter anything before the expert has a chance to investigate - and if you do have to alter it, first take pictures
Construction experts need to see the conditions as they exist. While it is appropriate to take emergency measures if necessary, such as cleaning up a flood or putting plastic over an area of the exterior where water is pouring in during the rainstorm, generally you want to let the expert see the problem in its current state. So, if you have to take emergency measures, first take some quick photographs of the current conditions. These could prove to be critical evidence later for your case or insurance claim
Your attorney should be the one communicating with your expert
There are a number of reasons why it is best to have your attorney be the point person for communicating with your expert. First, there may be other parties and experts who need to be notified of upcoming investigations. Second, the scope and nature of any expert investigation needs to be determined with the nature of your potential claims and the risks of "over-investigating" clearly in mind. And third, experts cost money, and if your expert is spending time answering questions that, although worthwhile, may not be directly relevant to your case, that could simply be money down the drain. With HOAs in particular, it is best if unit owners are not unnecessarily taking up the expert's time with questions.
Do not ask your expert to write a report without first talking with your attorney
Expert reports written for homeowners, associations, or commercial building owners can quickly become "targets" for defendants and insurance companies to try to pick apart. This can make it difficult and expensive for your expert to clarify or alter an opinion if additional information is obtained later on. Also, such reports may create disclosure obligations for you if you later sell your property. For these and other reasons, including the fact that reports can be expensive, it is probably best if you do not ask an expert to issue any reports. Have your attorney deal with the question of whether and when one of your experts should prepare a report.