Knowledge Builders

should a deck have a slope

by Tyreek Runolfsdottir Published 2 years ago Updated 1 year ago

A deck should slope ⅛” per foot perpendicular from a house. Regardless of deck orientation – which direction the deck boards run – a minimum slope of ⅛” is optimal for shedding water. If your deck surface is solid, then ¼” per foot is a better choice.

Should a deck be sloped or level?

Most contractors suggest sloping the deck 1/4th- 1/8th of an inch for every foot of decking. With this slope, the difference isn't terribly noticeable to those standing on the surface but your chance of ponding is reduced greatly.

Do you need to slope a composite deck?

Frame your composite deck You should include a slope of 1/16 inch per foot to allow water to move away from the walls. This will be part of the code structure for permits.

Does a deck have to be perfectly level?

In a nutshell, the easy answer is this—no, your deck should never be level with your home. That's because of the threat most feared by even the bravest DIYers and homeowners: water damage. If your deck or patio sits at the same height as your home, you're making it easy for water to get inside and wreak havoc.

Should you put a fall on decking?


What is the minimum slope for a deck?

A solid deck needs to be sloped between a 1/8″ (3mm) and ¼” (6mm) per foot to encourage water drainage. Decks with properly gapped decking boards require no slope as rain will naturally run off the boards even when level.

How much slope should a porch floor have?

Traditionally, boards are laid running perpendicular to the house. Make sure the porch floor has a slight slope to it—between 1⁄8″ and ¼” per linear foot for tongue-and-groove floors. (If the porch is deeper than 8′, use a slope closer to 1⁄8″ per foot to avoid a pronounced slant.)

Should a deck be flat?

Deck boards should have a slope of about 1/8” per foot. This allows water to easily slide off deck boards more efficiently during rainstorms.

Can house and deck be same level?

Timber-slatted decks can be installed at the same level as the floor inside to give level access but you must have a gap of at least 6-12 mm between your wall cladding and the deck to allow for drainage and prevent water pooling.

Do deck joists need to be perfectly level?

Deck joists do not need to be perfect, but they need to be consistent. How consistent depends on the decking material used. More rigid decking material will hide the joist inconsistency better. Deck joists supporting 1 ½” (38mm) or 5/4” (32mm) dimensional wood decking do not need to be planed.

How high should decking be from ground?

Make sure you build your deck high enough for ventilation so the ground can dry out. That way, your deck will last longer. Generally, if a deck is less than 12 inches above the ground, the perimeter of the deck must be open for free air to flow beneath the deck.

How high should decking be off the ground?

The height of the parapet depends on how far the deck surface is off the ground: For 'low-level' decks up to 600mm from ground level - parapet height should be 900mm. For 'high-level' decks over 600mm high – parapet height should be 1100mm.

Should there be a gap between decking and house?

A proper connection would have a 1/2” to 3/4” gap between the deck construction and the house to allow rain and meltwater from snow to flush through; this prevents rot from forming in the deck timbers, and/or in the adjacent wood of the house framing.

How much slope should a deck be?

A deck should slope ⅛” per foot perpendicular from a house. Regardless of deck orientation – which direction the deck boards run – a minimum slope of ⅛” is optimal for shedding water. If your deck surface is solid, then ¼” per foot is a better choice. Deck boards that run perpendicular to a house will have the width of each board abutting the house.

Why is the slope beneath a deck important?

Slope Beneath a Deck. The slope beneath your deck is arguably more important, particularly because this slope is where the water actually accumulates. Obviously, it should slope away from your home. Over time, pooling can occur in the earth beneath your deck.

Why is it dangerous to have a deck board perpendicular to a house?

This is dangerous because if you keep your deck level, you run the risk of water channeling down the width of the board into your house.

Why is it important to slop a deck?

The areas beneath a deck in which water falls cause depressions. These depressions can get quite deep, depending on your soil type, and sit for long periods of time. Over time that water can seep back into your house. This is why sloping your deck is important.

How wide should a deck board be?

Even deck boards that run parallel to your home should be sloped slightly away from your home. While a deck board is usually only about 6” wide, ...

Do deck boards shed water?

However, proper installation of deck boards – ensuring the best face is facing upwards – will negate any significant cupping and allow the slight slope of the deck to shed water. There is significant debate about which way to install deck boards to avoid cupping and, thus, retain water on top of deck boards.

Can you slope a composite deck?

While you could keep a composite deck level, some water would stay and eventually evaporate. Either way, a composite deck requires little or no slope. If your deck is not attached to or next to any structure, then sloping your deck still might be advisable if only to shed water off the deck boards more efficiently.

How to keep soil from holding moisture?

When sloping the ground, remove all sod to keep it from holding in moisture. When you finish sloping the soil and compacting it, you can cover the ground with 6-millimeter polyethylene to provide even more moisture protection. This works well if your deck sides will obscure the earth beneath so the plastic cannot be seen.

Can a concrete patio be sloped?

In this case, there is nowhere for water to go, so the concrete should be slightly sloped to encourage runoff. This is especially important for poolside concrete decks that receive a lot of a water. Use your level and trowel to make these decks slope downward out to the grass or pool, about 1/4 of an inch for every foot of space.

How much slope does a color guard deck ceiling need?

The UpSide Deck Ceiling from Color Guard requires about 4 inches of a downward slope for every 8 feet and the pitch will be set throughout the entire deck space by the convenient UpSide Q.I.T.

Do you need a deck pitch?

Deck pitches and slopes are generally just necessary for upper-level decks where a patio or storage space below would be desired. Otherwise, decks close to the ground and featuring deck boards that are installed conventionally with deck board gapping won't typically require deck frame pitches.

Why is my deck at the same height as my house?

If your deck or patio sits at the same height as your home, you’re making it easy for water to get inside and wreak havoc.

How much does a deck cost per square foot?

While a beautifully installed deck or patio can be an expensive project ranging between $15 and $30 per square foot, there’s no doubt that it can also add value to your property and joy to your life. Just make sure you get that slope right to make sure your happy home is also a dry one.

Why are deck boards dropped?

The slatted boards make it easier for water to leave your deck on those rainy days. Decks and patios by their very nature are more exposed to the elements than most of the other parts of your home. That is why decks are typically dropped 1/8'' per foot. To be too level with the home could lead to extensive water damage.

Why do you need flashing on a deck?

The Flashing. Deck flashing is critical when it comes to making sure you keep unwanted moisture (in other words, all moisture) away from your home and its foundation. Flashing connects your deck to your home while redirecting water away from it .

What are the joists on a deck made of?

Moving away from the house itself and into the deck, we have the deck joists. These long, central, perpendicular beams are most commonly made of wood. They also serve as the main supports of your deck.

What is a deck made of?

Every deck is made up of several different components including bridging, decking, railings, and supports . However, we’re going to spend our time here talking about the parts of the deck that are the most affected when you build your deck level with your home.

What is a patio?

A patio or a deck can totally transform the entire vibe of the place that you call home. If you’re new to the world of indoor space meeting outdoor space, you’re going to have a lot of questions before building your deck.


1.When and How Much Should You Slope A Deck? - Decks …


10 hours ago Most of the time, you should have sloped decking. Ideally, the slope should form away from the house, as you don’t really want water pouring directly into your living room. However, if your deck is freestanding, then a slope is not entirely necessary, as it doesn’t matter which direction the water travels in.

2.Should A Deck Have A Slope? - Plasticine House


5 hours ago  · The decking should slope away from the house at a fall of 1:100 and so you need to drop the deck by 10mm for every 1 metre of the deck. The ground should slope slightly towards the outer edge (away from the property) of the decking to allow adequate drainage.

3.Garden Guides | How Much Should a Deck Slope?


36 hours ago When decking is installed conventionally, with gaps between adjacent boards, sloping the deck surface is not necessary. Some decking products with limited drainage recommend sloping the deck frame to a 1/4” vertical per 12’ horizontal pitch.

4.Guide: Decking Slope For Drainage - DecksDirect


35 hours ago  · How Much Should a Deck Slope? Deck Slope. There is a difference between talking about the slope of the ground for a traditional deck, and the slope of... Concrete Slope. A concrete deck or patio is the exception to the deck slope rule. In this case, there is nowhere for... Ground Slope. When ...

5.Does My Deck Need to Be Level With My House? - Angi


10 hours ago  · If your deck is attached to your home and its boards run parallel to the house, your deck should have a slope. it’s best if your deck has a slope of about 1/8 of an inch per foot to ensure that water flows away from your home. If your deck is attached to your house, and the boards run perpendicular to the house, you don’t need a slope because the gaps between the deck boards should drain rainwater …

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