Dek-Block veterans, please come share your stories.

July 20, 2009 8:51 AM

Thinking of building a platform-style deck in our backyard using the Dek-Block system. Looking for experiences from others who have used it.

Considerations:
We've already checked with our city and found that the floating foundation system is permitted.
We know we aren't required to have frost footings as long as it's not attached the house.
We won't need to pull a building permit because the deck will be less than 30 inches from deck to grade.

So, my questions are:
Has anyone here used it?
If so, are you happy with it?
Is it as easy to put together as they say?
Any pitfalls to be aware of?

Thanks!

posted by anderjen to Home & Garden (4 answers total)

I've used them. The issues with them are:

The ground has to be prepped beforehand, be compacted and leveled. In my experience, they don't move much after installation, but the soils in my area are clays over limestone. They don't compact much.

You define the slope in your deck when you lay the blocks. This is the major limitation of the system. There's not a lot of room to adjust or shim for height. This is where ground prep is important. I normally try for about 1/4" to 1/2" fall in 1' of deck (0.5-1.0 cm in 30 cm), sloped away from the structure wall. This prevents rain from being trapped against the house.

The deck will gap off the house. I've seen people use a flexible strip off of a structure to cover the gap between the deck and a wall. You can't attach to the structure directly, but you can put a flexible covering over the gap. This is more cosmetic than anything.

For simple decks these seem to work pretty well and are fairly durable. I know of at least one dek-block deck that has survived 10+ years. In my own use, they were stable once installed and caused no problems do the line. They work as advertised.
posted by bonehead at 11:03 AM on July 20, 2009

I haven't used Dek-Block products...but I have done similar work with lots of site prep like Bonehead mentioned. I would highly recommend investing in a line level, tripod, and sighting stick like those on this page:

Surveying Levels

Something like this will make your site prep 500% easier than using a clip-on string level, a tube with water, etc. You need two people, but this is one of the best tools for even basic outdoor house work. Use it for the grading, block setting, go back through and check heights of every block or 4x4 post riser, etc. You can then check and re-check easily throughout various points in your building. You can't really shim the Dek-Blocks if you are putting your support beams directly on them, but you could always re-cut a post if needed if you're using the Dek-Blocks that way.

You will also use the level again for many jobs you may encounter in the future - erecting fence, retaining walls, etc. A decent "starter" set will cost around $200, but well worth it in my opinion (shop around to find a good price). So this isn't just a tool you will use only for this deck job. Although in my opinion DIY home-projects are great excuses to collect cool tools...
posted by JibberJabber at 1:02 PM on July 20, 2009

I'd definitely use any system that avoids attaching a deck to a house. Ask an established remodeller/contractor - lots and lots of horror stories about damage to houses caused by decks.

So even if it isn't perfect, it is better than what most folks do.
posted by yesster at 6:03 PM on July 20, 2009

Really late here, but chiming in to say that I built an octagonal deck with Dek-Blocks in a quiet corner of a former back yard. It was ridiculously easy, held up really well. The ground prep I did could best be described as "bare minimum", I think I raked a bit, laid out the blocks, then checked for level and added/compacted soil under the low blocks. I'd recommend the system whole-heartedly.
posted by donnagirl at 7:27 PM on July 22, 2009