Le propriétaire du bâtiment veut installer des panneaux solaires sur la toiture neuve.

In French, de + le always contracts to du.

• de le bâtiment → du bâtiment

So du bâtiment literally means “of the building” or “from the building”.

You only write de le if le is part of another word (like a name: de Leonardo), not when it’s the article le. The same thing happens with à + le → au (e.g. au bâtiment).

Propriétaire means owner, and depending on context it can also correspond to landlord in English.

• If we’re talking about a residential building where people rent apartments, le propriétaire du bâtiment can be understood as “the landlord / the building’s owner.”
• In a more neutral or technical context, it’s simply “the owner of the building.”

So the French word is broader; it covers both “owner” and “landlord” depending on the situation.

Propriétaire has the same form for masculine and feminine; the gender is shown by the article:

• Le propriétaire = the (male) owner
• La propriétaire = the (female) owner

So if the owner is a woman, the sentence becomes:

• La propriétaire du bâtiment veut installer des panneaux solaires sur la toiture neuve.

Nothing else in the sentence needs to change.

Here are the key nouns with their genders:

• le propriétaire – masculine
• le bâtiment – masculine
• le panneau / les panneaux – masculine
• le panneau solaire / les panneaux solaires – masculine
• la toiture – feminine

Adjectives must agree in gender and number with the noun they describe:

• panneaux solaires
  • panneau is masculine singular → panneau solaire
  • panneaux is masculine plural → panneaux solaires (add -s to the adjective)
• toiture neuve
  • toiture is feminine singular → neuve (feminine form of neuf)

So:

• masculine singular: neuf
• feminine singular: neuve
• masculine plural: neufs
• feminine plural: neuves

In French, some verbs can be directly followed by an infinitive without any preposition. Vouloir is one of those verbs:

• vouloir + infinitive
  • Il veut installer… = “He wants to install…”
  • Je veux apprendre le français. = “I want to learn French.”

You do not add de here:

• ❌ veut d’installer
• ✅ veut installer

Other verbs that behave similarly: pouvoir faire, devoir faire, savoir faire, etc.

des is the indefinite plural article (“some”), while les is the definite plural article (“the”).

• des panneaux solaires = some solar panels (unspecified amount / not talking about a specific set already known)
• les panneaux solaires = the solar panels (a specific set that the speaker and listener both know about)

In this sentence, we’re introducing the idea that the owner wants to install solar panels in general, not a particular known set of panels, so des is more natural.

Panneau is the singular form; panneaux is the plural.

• Singular: un panneau solaire
• Plural: des panneaux solaires

Spelling:

• Many French nouns ending in -eau form the plural with -eaux:
  • un bateau → des bateaux
  • un château → des châteaux
  • un panneau → des panneaux

Pronunciation:

• panneau: roughly /pa-no/
• panneaux: exactly the same pronunciation /pa-no/
  The x in panneaux is silent; it only shows the plural in spelling, not in sound.

Both relate to “roof,” but they’re not used in exactly the same way.

• le toit
  • the roof in a general, everyday sense
  • very common word
• la toiture
  • the roofing / roof structure / roof covering
  • more technical or specific, often used in construction, architecture, or formal descriptions

You could say:

• …installer des panneaux solaires sur le toit neuf.

That would be grammatical and understandable. Nuance:

• sur le toit neuf – slightly more everyday and generic (“on the new roof”).
• sur la toiture neuve – sounds a bit more like construction terminology (“on the new roofing/roof structure”).

Context (legal, technical, or architectural) often prefers toiture.

In French, most adjectives normally come after the noun:

• une maison neuve – a new house
• un ordinateur portable – a laptop computer
• une voiture rouge – a red car

So toiture neuve follows this standard pattern: noun (toiture) + adjective (neuve).

Some common adjectives do usually go before the noun (e.g. beau, bon, petit, grand, nouveau), but neuf / neuve typically comes after the noun.

• ✅ une toiture neuve
• ❌ une neuve toiture (sounds wrong / unidiomatic)

Both can translate as “new,” but they’re used differently:

• neuf / neuve

  • emphasizes that something is brand new, unused, often just built or just manufactured.
  • une toiture neuve = a newly built roof / brand-new roofing.

• nouveau / nouvelle

  • emphasizes “new to me / new in this situation”, not necessarily brand new.
  • un nouveau bâtiment = a new building (for this company or neighborhood), but it might not be brand new in an absolute sense.

In this sentence, toiture neuve focuses on the fact that the roof has just been constructed or redone.

French prepositions here work much like English:

• sur = on / on top of (contact with the surface)

  • sur la toiture = on the roof (in contact with it)

• dans = in / inside

  • dans la toiture would mean “inside the roof,” which is not what you mean for installing solar panels.

• au-dessus de = above / over, not touching necessarily

  • au-dessus de la toiture would be “above the roof,” like something floating or hanging over it.

Solar panels are mounted directly on the roof, so sur la toiture is the correct choice.

Yes, you can say:

• Le propriétaire du bâtiment voudrait installer des panneaux solaires sur la toiture neuve.

Difference in tone:

• veut = wants (simple factual want; more direct)
• voudrait = would like (more polite / softer / more hypothetical)

So veut states a straightforward intention; voudrait sounds a bit more tentative or polite.

French often uses the definite article (le, la, les) where English uses a possessive adjective (“his, her, their”), especially when the possessor is already clear from context.

We already know whose roof it is:

• Le propriétaire du bâtiment… → it’s his/her building, therefore also his/her roof.

So French can simply say:

• sur la toiture neuve = literally “on the new roof,” but understood as “on his/her new roof.”

If you really want to emphasize possession, you can say:

• sur sa toiture neuve = “on his/her new roof.”

Both are grammatically correct, but la toiture neuve is perfectly natural here because the owner has just been mentioned.