Base is soggy

Affects quality

The most common single cause is under-preheated equipment combined with excess topping moisture.

Ask yourself

#1
Excess moisture from sauce or toppings
Strongly supported
High-water-content toppings (mushrooms, fresh tomato, under-drained pineapple) release liquid onto the base during baking.
#2
Baking surface not preheated enough to set the base quickly
Strongly supported
A cooler surface takes longer to set the base, giving moisture more time to soak in before the crust firms up.
#3
Bake time too short or temperature too low for the moisture load
Generally accepted
A quick, hot bake evaporates surface moisture faster than a slow, cool one.
#4
A thin peel, screen, or pan with low thermal mass, specifically when the sogginess is concentrated in the middle rather than the whole base
Generally accepted
A thin baking surface has little stored heat to give up as the pizza's centre — the last part of the base to firm up — needs it; the edges often set fine from residual ambient oven heat while the middle stays underdone and absorbs moisture. A stone or steel with real thermal mass fixes this specifically, where simply baking longer often just overcooks the edges instead.

The same symptom has different answers on different equipment. Each branch below states how to tell whether it is yours.

Pizza in a domestic ovenStrongly supported
How you would know: The base is wet specifically in the middle, under the sauce, while the rim is dry and cooked.
Not enough bottom heat to evaporate topping water as fast as it arrives. In a domestic oven baking on a bare shelf or an unheated tray, the base is the coolest part of the pizza throughout the bake.
Do now: Move the pizza directly onto a preheated surface for the last two minutes, or onto the oven's lowest shelf.
Change next time: Fit a stone or steel and preheat it fully, and reduce the water going on in the first place — strained sauce, drier cheese, pre-cooked vegetables.
Pizza on a baking trayGenerally accepted
How you would know: A tray-baked pizza is soft and pale underneath with no crisping at all.
The tray was floured or used dry rather than generously oiled. On a low-mass tray, oil is the mechanism that conducts heat into the base — without it there is nothing to crisp against.
Do now: Little can be done mid-bake; move it as low in the oven as possible.
Change next time: Oil the tray properly — more than feels right — and use the heaviest, darkest tray you own. Consider preheating a second tray beneath it.

Finish briefly on a very hot surface or under a broiler if the top is already done but the base isn't set

Pre-cook high-moisture toppings, preheat the baking surface thoroughly, and don't over-sauce

Guides that treat this as an outcome to improve, an environment to work with, or a flavour to understand, rather than only a problem to fix.