It all depends, mostly on the materials used, salinity, pH levels, oxygen concentration, temperature, availability of calcium carbonate and water currents/waves.
These effects are non-linear, for example corrosion rates generally increase with temperature, but if you raise the temperature further in can slow corrosion by removing oxygen (among other things).
Calcium carbonates (e.g. limestone) in the water can deposit scale that protects the underlying materials. You often see these scales on water pipes. These scales can protect the materials for a long time.
There are many examples of buildings and towns that have be submerged for long periods of time. Many are intentional as a result of building reservoirs, but almost all of these are fresh water.
Since we build ships, we have also studied the issues associated with submerged materials used in ships.
Building materials. Sheet rock is rapidly ruined. Wood treated with creosote survives for a long time, 50 or 100 years is usually not ruined. Creosote is not much used anymore for marine applications due to environmental concerns. The other treatments are not as effective, but I don't have actual survival times. Plywood may delaminate within a few years depending upon the glue.
Steel -- Steel used in construction is rarely stainless, so corrosion begins immediately as even fresh water always conducts current. Depending upon the other materials this may be accelerated greatly because of galvanic effects. In fresh water the rate of corrosion depends upon very minor environmental differences, including the consistency of the steel the result is often pitting where the slightly more corrosive gets used up in preference to the other areas. Experimental data is not even particularly accurate because the results are so variable. Salt water is just a worse problem as electrical conductivity is high.
Some coatings will protect steel for quite a while (even decades), but they all eventually fail due to imperfect coating and leaching of the material. Zinc-dipped steel is best known and for good reason. It is very effective as coverage is nearly perfect and the Zinc will be sacrificed first during corrosion. It will still fail eventually (cracks in the coating, etc.) but I don't expect this to be common in construction. 561
It certainly is not used for the steel fasteners that many construction depends upon. I.e., once the nails go, the building collapses.
For a nice online guide that gives a hint of the difficulty see Fundamentals of Metallic Corrosion in Fresh Water
Windows may tend to survive better than you might expect because they are frequently designed to resist moisture problems, so the wood is treated and the glues are moisture resistant. Still, just observe the deterioration of a leaky window and you will know that they really don't survive that well.
So what does last? Stone and kiln dried ceramics. You might get thousands of years from some of these. However, the mortar is first common point of failure. Some mortars can fail within a decade, others might last for a hundred years or even somewhat longer. If you have mortarless stone construction and you don't have problems due to earthquakes or excessive currents or wave you could like there when the waters recede a few centuries later.
The end result of all this variability is that we don't simply design construction to last for 50 years in underwater environments. We design the best we can and begin a program of inspection and maintenance. We have to inspect because we don't know when failure will occur and the maintenance is needed because failure will occur if we don't prevent it.
So what about 1 year of submersion. Any structure would require cleaning, refinishing, etc. before it would be usable. Note that most flooding also means sewer overflows are included in the floodwaters. Definite intensive cleanup is required and well as repainting, etc.
In general terms.
Wood -- unless specially treated for water, the wood will be damaged beyond what you would wish to use. This includes most windows as construction materials are often selected based on price than quality in residential usage. Plywood is even less likely to be usable as water can interpenetrate common plywood more easily than bulk wood.
Steel -- unless specially treated for water, significant corrosion will be present making the cost of cleanup very high. If steel fasteners are used in construction, it will be unsound (or at least not provably sound)
Brick, concrete, stone -- Most mortars should survive and be safe to use after a year underwater provided they have had sufficient time to cure completely prior to flooding -- still a nasty cleanup job will be needed and the organic materials, etc. will get into every nook and cranny. 87