A pergola is an outdoor garden feature consisting of vertical posts that shade a sitting area on a deck or a garden or walkway. You can build a pergola directly on the ground or on an existing deck.
Pergolas built from the ground are more stable than those built on existing decks.
However, you can build a secure pergola over your existing deck using thick galvanized steel fasteners to strengthen the pillars.
Other things to keep in mind when building a pergola on deck include:
• Using pressure-treated wood that can withstand a lot of pressure. When choosing wood, go with ACQ-treated wood because it will prevent damage by insects and water.
• Adding railings between the wooden posts. Railings give more strength to the structure against strong winds.
• Avoid adding heavy roofing materials like canvas and wood covers that could make the pergola unstable. The best materials for additional shade on the roof include fabric panels or light wood lattices.
• Attach the support posts to the joist structure under the deck.
These tips will prevent your pergola from tumbling down due to strong winds or heavy rain.