There are a number of problems.
1: Plastics. If you look at newer construction it makes extensive use of plastics which are not only extremely flammable, (much more so than wood once they get going) they- and toxic smokes they produce once burnt, also contain endocrine disruptors which are a subject in themselves, These persistent organic chemicals also persist in the environment and build up in living things bodies where they threaten reproduction, cause cancers and neurological problems, make people morbidly fat and cause metabolic syndrome, diabetes, and an endless list of other health problems, at a huge and growing cost to society (a cost
already estimated at 2% of the current EU GDP) and its growing.
2. Fake wood products - again tons of problems, including catastrophic structural failure under some conditions ( "delamination",) offgassing of known carcinogens, tendency to grow toxic molds if used in places where prone to condensation, in the case of some hybrid fiber/plastic products, offgassing of vapors some of which have similar problems to 1, and so on.
3.) Foams which contain plastics are very strong and very light but need to be protected from flame. Also many contain
4.) flame retardant chemicals that may be just as dangerous as fires.
5.) In the US, especially, paper covered gypsum wallboard, and mold. Molds produce some of the most toxic/carcinogenic/potentially health destroying chemicals known to mankind when subjected to (very) high humidity conditions.
There are some obvious solutions - Modern energy efficient windows can drastically improve the live-ability of older buildings and are a really good investment. But, what to frame them with?
Larger, existing buildings are not so easy to retrofit.
for example, -look at what happened to the vinyl windows at grenfell.
New construction can be energy efficient but relies too greatly on the materials mentioned which are problematic.
Passive solar design can make *homes* that require little heating and cooling much of the year, much of that they need can be provided by powered ventilation and in some cases, the ground, which stays at a fairly constant temperature - in small dwellings, that reservoir can be utilized for both heating and cooling.
But for ideological reasons, starting with the shift in the 90s and the WTO agreement on services, now governments can't/don't want to help families that need them get services, they are forced to hire commercial firms, so the solution of building well built homes for families has been put out of reach, and indeed, all forms of subsidized services, if they have not already, will likely soon run into problems in trade agreements.. Basically, governments have signed and are signing giant worldwide permanent, irreversible non-compete agreements with multinational corporations that cant be fixed by voting once services are deregulated. (So the deregulatory changes now going on in health care in the US and UK will become permanent, due to the deals "ratchet' an important fact Americans and Britons are being denied)