Decking Above Damp Proof Course (DPC Checked Out)


Decks can be either of two types, an elevated deck or a ground-level deck. You may construct a combination of the two if necessary. Dampness is among the leading factors that determine precisely how you should have your deck built, primarily when the deck intends to attach to a piece of property.

So, can you put a decking above a damp proof course? Putting decking above damp proof course in not recommended, especially if the intention is to extend a property with a deck. The deck should be designed to be not less than 15cm below the actual damp course. After attaching the deck, the installers shouldn’t directly attach the deck to the property. A 1cm gap between the decking and the house should be left.

Decking should always remain beneath the damp proof course when being attached to the property. The top of the deck must stay 150mm below the damp proof course at the very least. The requirement is in line with meeting the building regulations.

A damp proof course stops water from soaking up the bricks and getting into your house. However, placing things against the wall allows rain to splash against the part of the wall above the DPC: this would lead to the wall soaking and dampening the indoors.

If the paving you are working on is too close to the damp proof, you might need to dig a few inches deeper. By digging deeper, you ensure that the decking won’t go over the recommended level when laid. Deeper digging requires that you first determine the location of the buried cables and pipes. That way, they’ll remain safe from any damages during the process.

Use an efficient cable avoidance tool to check and detect where all the significant cables situate in your compound. Most likely, pipes will be around and next to your house. However, there may be more pipes in the garden supplying your neighbors. After identification, plan your decking accordingly.

The smallest mistakes in construction could lead to future dire and expensive consequences. We’ve prepared a guide on the reasoning behind the height of your damp proof course.

Does Decking Cause Damp?

The wrong height placement of decking can lead to the creation of damp patches along the house’s rear. Failing to have a slope on either side of the decks leads to them becoming slippy and moldy.

Sometimes, the decking isn’t always the cause of damping; if the walls face the rain’s direction, they will get wet and possibly spread the dampness. Weatherproofing your structure before embarking on construction prevents damp moisture on walls from rainwater.

Since the decking is usually immediately outside the house, they often tend to go across the doorway. Such decking should slope a little bit from side to side. By creating a space between the wall and the decking and staying at least 150mm underneath the damp course, you avoid the splashing water. Specifically, you prevent the splashing of rainwater bouncing at the deck, keeping the deck dry.

If the dampness is a result of a decking misconstruction, then it can be corrected. Check whether it is possible to release every fixing bolt from its correspondent wall plate. Next, insert some stainless washers to create about a 10mm gap. Finally, refill the bolts. Better still, get a new professional to undertake the correction for you.

Must I Get Permission for Planning To Get a Raised Decking?

Fortunately, you do not require any planning permission to make yourself a raised decking course. However, the allowance is limited to decks under 30 cm in their height. Additionally, the decks should combine with other outbuildings like sheds. The deck also shouldn’t cover over half of your garden.

If your decking has a fence, then it shouldn’t go higher than your fence. To prevent any other problem, ensure you liaise with your neighbors. The new decking build should not carry a negative impact on neighbors.

Can I Build a Decking Area Myself?

After going through a YouTube DIY video, installing your decking might seem like an excellent idea. However, it’s essential to check whether you have all the requisite skill sets and tools. It’s the first step in getting a professional finish. Next, it’s of great significance that you ask for a price quotation from a specialist in decking. If all of this positively seemed possible to you, then go right ahead.

However, if you lack the skills in woodworking ( carpentry) or you lack the tools required, it’s a lot cheaper to hire a professional. The slightest of mistakes could lead to dire consequences in your finished product. Hiring a professional saves you from any possible risks involved in the construction.

Designing a Decking Area

The first consideration you need to make is the height. Decide on whether you are seeking a decking that is a small step from the ground. Alternatively, are you seeking one with multiple stages that lead up to it? The difference is that if you make one with fences, you must ensure the height is permissible regarding planning permission.

If you have any doubts about your decking area and permissions, contact the local planning agency for advice. Next, choose the outlook of the decking area. There are four primary ways you could arrange your board:

  • Horizontally: Horizontal decking boards have a traditional look and feel to them.
  • Chevron Style: These boards are usually shorter and laid similarly to parquet flooring. For this, you need to get a composite decking calculator to get how many meters of the decking board you require.
  • Diagonally: These decking boards are just a contemporary twist on the horizontal ones
  • Picture frame style: Picture frame boards are a type of decking whose finishing makes a statement. Usually, the design incorporates three or two long deck boards to create a border. Following the barrier, fill its insides with some diagonal slats.

How To Protect Your Deck From Damage by Water

While damp proofing your decking area, it’s vital that you protect the deck itself from damage caused by water. Moisture can and will cause damage on your deck if unprotected. The damage may not occur overnight, but the gradual, since consistent exposure to elements eventually takes a toll.

One undeniable sign that your deck has undergone moisture damage is mildew and mold growth. You begin to notice damp and dark spots in areas like underneath a pile of leaves or under a rug. Piles of leaves could harbor the growth of fungi and mildew that feed on the deck’s wood.

When a puddle sits on a deck board, it sips in. In a few hours, the paddle will dry up, but some of its moisture will find its way into your wood. Over time, the unprotected wood will warp, damaging your deck in the process. However, there are simple steps that can save your deck from water and element damage.

To begin with, choose lumber that has undergone pressure treatment. Aside from treated lumber, conduct an annual re-sealing. Resealing ensures that any moisture stays locked out, which essentially prevents any water from soaking onto your surface. Sealing also stops water from going down into crevices and cracks.

By taking these few measures, you’ll prevent your deck from getting any mildew grown and mold; thus, retaining its beautiful appearance.

Final Thoughts

There’ll always be different ideas when it comes to deck construction. However, the requirement on the height from the damp proofing course is a static factor that any constructor should observe. Irrespective of which design you want, ensure that your decking is built at least 15mm below the damp proofing course.

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