In a prepositional phrase, use a noun (not a verb) after the preposition.
Sometimes the noun will be a gerund, the -ing verb form that functions as a noun.
to as preposition vs. to as infinitive marker
Distinguish between the preposition to and the infinitive marker to. If to is a preposition, it should be followed by a noun or a gerund.
If to is an infinitive marker, it should be followed by the base form of the verb.
Test
To test whether to is a preposition or an infinitive marker, insert a word that you know is a noun after the word to. If the noun sounds right in that position, to is a preposition.
In this case, a noun (such as magazines) makes sense after to, so to is a preposition and should be followed by a noun or a gerund: Zoe is addicted to magazines. Zoe is addicted to reading.
In this case, a noun (such as house) does not make sense after to, so to is an infinitive marker and must be followed by the base form of the verb: They are planning to build a new house.
Related topics:
Prepositions
Prepositional phrases
Gerund phrases
Infinitive phrases
prepositional phrase A phrase beginning with a preposition and ending with a noun or noun equivalent (called the object of the preposition): on the horizon.
preposition A word placed before a noun or noun equivalent to form a phrase modifying another word in the sentence: They fell in line with the crowd.
gerund A verb form ending in -ing and used as a noun: typing, thinking.