Deck replacement

[SimonStevensCanes]

Our house has a large (41m2) deck that we inherited with the house and now has rotten away and needs replacing. I'm loath to replace the frame with something that can rot away and will need replacing in another 10 years. I've looked at composite, and whilst I think I'm sold on the boards, the frame is an obscene price.

I've been wondering about using concrete beams (as in used with beam and block floors). I'd face the top with composite (as an easier layer to screw in), and I guess I'd have to brace (noggins?) between each, which would be something that could rot (too expensive to do that with composite I think).

Does that sound mental, or would it be a durable solution?

 

[Spectric]

If you use all composite it will be a much easier job and lighter. Concrete lintels for block and beam are heavy and would need more substantial footings to take the weight but feasable.

 

[SLM]

Have you looked at recycled plastic? It’s a bit more than timber, but has the advantage of lasting Linder than you.

It doesn’t have the aesthetic qualities of composite (if that’s bag), but for the unseen structure, it’s brilliant stuff.

 

[SimonStevensCanes]

If you use all composite it will be a much easier job and lighter. Concrete lintels for block and beam are heavy and would need more substantial footings to take the weight but feasable.

Yeah definitely would be easier I think. It works out an extra £2-3k by my reckoning though.

Useful tip on the footings, I hadn't considered that. I had planned to support the lintels along their length every couple of foot (to avoid any bounce), which I guess would spread the weight some. But yeah, I should probably consider some proper footings, rather than the paving slab I had in mind

 

[SimonStevensCanes]

Have you looked at recycled plastic? It’s a bit more than timber, but has the advantage of lasting Linder than you.

It doesn’t have the aesthetic qualities of composite (if that’s bag), but for the unseen structure, it’s brilliant stuff.

I hadn't twigged that recycled plastic != composite. Looking again at what I've been looking at.. I had been looking at composite joists that are intended for use on a hard surface as they are cheaper than their (bigger) recycled plastic counterparts.

With the company I'm looking at (of course I'll shop around once I have an idea of what direction to go in), their calculator estimates £4680 for just the subframe made from recycled plastic.

Thanks for pointing out the difference, very important to know

 

[SLM]

With the company I'm looking at (of course I'll shop around once I have an idea of what direction to go in), their calculator estimates £4680 for just the subframe made from recycled plastic.

Thanks for pointing out the difference, very important to know

That’s expensive! Definitely not the same product that I’ve looked at. Worth looking around; the product I’ve seen is not pretty, with a distinctly recycled look! It is more costly than treated timber, bet certainly not that much more!

I’ll post a link, when I have time.

 

[SimonStevensCanes]

That’s expensive! Definitely not the same product that I’ve looked at. Worth looking around; the product I’ve seen is not pretty, with a distinctly recycled look! It is more costly than treated timber, bet certainly not that much more!

I’ll post a link, when I have time.

Thanks, I'd appreciate that

 

[SLM]

Thanks, I'd appreciate that

From memory, one of the suppliers is in Wrexham, so not a million miles from you

 

[MikeJhn]

I use concrete fence posts for all sort of foundations, usually levelled with roof tiles and earth packed underneath, my garden office is over twenty years old and has not moved.

 

[Spectric]

Using timber as the support frame should not rot in ten years if done correctly, what you must ensure is the timber is not in direct contact with the ground and there is airflow through the structure and use treated timber.

 

[Chief Sawdust Maker]

I have built many decks for customers of varying sizes over the past 20 years using all manor of deck boards softwood hardwood anti slip composite
The one that has held up the best is 20 years old was built with treated joists and treated softwood decking, all of the metalwork was galvanised and also painted with red oxide paint all of the screws were stainless and damp proof membrane was placed between the joist and joist hangers The decking was secured using good quality deck screws and no nails were used.
The customer jet washes the deck every spring and once the deck is dry give it a really good coat of Danish oil, It looks as good today as it did when it was built.
I am due to build one at my own house for the worlds most demanding customer (my wife) and it will mirror the 20 year old one the key is to buy the best timber you can afford take care when building it and ensure its oiled ever year

Good luck and enjoy your deck

 

[BucksDad]

Have you looked at steel frame as support for your deck. They are quite popular now. I got a quote for a steel frame building for my workshop in my garden but didn't want the thick walls or cold bridging.

I got a quote from this place on ebay I think - steelframestructures on eBay Although they list garden rooms, I am sure you could just ask for a base!

Here's a similar one with a price per m2 - Steel Deckframe System Galvanised Steel Deck Framing

I am sure if you google you can find some others.

That + composite really will be a deck for life!

 

[XTiffy]

I built a house twenty years ago with a very large deck area. I used 6x2 treated joists supported by galvanised strap hangers concreted into the ground. (6" circular hole using auger) Ten years later the timber decking rotted (the then owner didn't treat the decking). The professional company quoted for a full strip out and replace but realised the joists were in perfect condition, so just relaid new decking. So it definitely works.

 

[GuitardoctorW7]

I built mine during Lockdown which gave me something therapeutic to do, it's composite with a wooden frame (treated fence posts and beams) the posts are set in Postcrete having been treated with bitumen paint on the bit that goes in the hole. I did also tack strips of plastic damp course over the top of the beams partly to deflect water off and partly because the wooden beams look ugly showing through the gaps.
Couple of observations (I personally found).... Don't start at the back and work forward as the composite manufacturers instruct. Unless you're incredibly precise and build the deck perfectly you'll end up with a fillet. The eye is much more forgiving when it's at the back.
The manufacturers recommended buying +10% to allow for error, and in hindsight not sure that's wise especially with such an expensive product. I cut fairly accurately and rather than waste lengths I found it easier to just put in an extra noggin or two. I consequently ended up with a few planks left over which I turned into planters.
It's not scratch resistant, and it's not easy to remove scratches with a wire brush as they also claim. You will scratch the boards but after a bit of use they seem to blend in.
The boards do get grubby, but I have a Karcher and the deck scrubbing attachment and it takes 1/2 an hour once a year to bring them back to looking good.
The afore mentioned hindsight is a wonderful thing. I really wish I'd made a jig to shave .75mm off the sides of the spacers as the gap is too big IMHO. I know you have to allow for expansion gaps but even last year when we historically hit 40C and it baked all day it hardly moved at all.
I also put galvanised wire mesh around the perimeter inside the frame to discourage Foxes from making a den.
I know I'm gonna get flack from some quarters saying "I should have done this... blah... blah" but my neighbours' son in law, who does it for a living offered me a job as he was very impressed.
I reckon this deck is good for 25 years or so before serious maintenance and I'll be well gone by then.
Good luck

 

[LarryS.]

At the prices you’re looking at it may be worth considering a patio ? We did 40m2 for about 6 grand , never rots and doesn’t need treatment

 

[SimonStevensCanes]

At the prices you’re looking at it may be worth considering a patio ? We did 40m2 for about 6 grand , never rots and doesn’t need treatment

yeah I've been thinking that I need to cost that up as it is an alternative.