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Shed / Garden Room flood protection


daiking

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Not something I’ve considered before but what would the consequences of a timber frame insulated shed being flooded out?

 

What’s ruined? And what can be dried out and refurbished? Are some insulation materials better than others for this?

 

is there a reasonable compromise for low cost construction but reasonable flood survivability? 

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Are you saying your shed has flooded?

 

Ours did in the old house but it was just a plain shed with no insulation.  I dried it out and 17 years later it is still fine.

 

If it's lined with plasterboard that will be shot for a start.

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14 minutes ago, ProDave said:

Are you saying your shed has flooded?

 

Ours did in the old house but it was just a plain shed with no insulation.  I dried it out and 17 years later it is still fine.

 

If it's lined with plasterboard that will be shot for a start.

 

My shed hasn’t flooded and it is only a shed which I know would dry out as long as it wasn’t washed away...

 

but I’m looking to replace the shed with something more civilised and realise that an important part of the design will be flood considerations.

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Standing water or flowing water?  

 

Our risk comes from flowing water if the burn over tops.  The shed next to it could flood (that bit of ground is lower than the garden on the house side)  But it would dry out very quick once the burn went down.  I could probably do a reasonable job of protecting the shed with some barriers to make the water flow around, rather than through the shed if I thought it much of a risk.

 

A lot of the flooding you see on the news lately is standing water and might take days to subside and little prospect of preventing it. That is much harder to protect, you can't just divert standing water somewhere else.

 

Stand it up on stilts above the highest ever known flood level?

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37 minutes ago, ProDave said:

Standing water or flowing water?  

 

Our risk comes from flowing water if the burn over tops.  The shed next to it could flood (that bit of ground is lower than the garden on the house side)  But it would dry out very quick once the burn went down.  I could probably do a reasonable job of protecting the shed with some barriers to make the water flow around, rather than through the shed if I thought it much of a risk.

 

A lot of the flooding you see on the news lately is standing water and might take days to subside and little prospect of preventing it. That is much harder to protect, you can't just divert standing water somewhere else.

 

Stand it up on stilts above the highest ever known flood level?

 

Similar situation with a stream passing the garden. Yesterday the water came through bottom of the fence which is the highest I’ve ever seen it.

 

I’m looking to build a fully insulated and well specced outbuilding in this spot. Realistically, stilts is not an option due to PD rules.

 

what happens when a TF house gets flooded? Do they just dry it out? Does the manky insulation dry out ok? Never smell?

 

 

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37 minutes ago, Onoff said:

You could build it on a base that would float upwards. Maybe with some tethers or 4 retaining posts that it slides up within.

 

I think the word you’re looking for is barge.

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I would perhaps think in terms of waterproof foundations which can be made higher later.

 

Could be something as simple as piles of breeze blocks that can be added to later. if I were being flooded in 10-20 years.I would just make it a bit taller on my own Initiative.

 

The one consideration may be a shed structure strong enough to take being jacked up?

 

If you are after something posh does this imply a site office or static caravan type thing?

Edited by Ferdinand
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I would think in terms of a "non floodable" foundation.

 

I think along the lines of an old cottage in the village where I used to live.  It was a 200 year old listed building, and regularly flooded, but not by much.

 

When it had a full renovarion, a new concrete floor slab was cast, with upstands all round the outside.  The entire floor and 6" up the walls was tiled with quary tiles.  Whenever it flooded, they went through the normal routine of stand the furniture up on blocks and allow it to flood, only ever to a few inches deep, then when it wend down scrub it all out and put the furniture back.

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34 minutes ago, ProDave said:

EPS is used for floats for pontoons and houseboats.

 

It was also used in the foundations of a car park with not quite the desired effect when it flooded 

Flood1_trans_NvBQzQNjv4BqaEgzq2T416ueS6X

 

Ah yes the car park in Crayford just down the road from me.

 

MANY years ago in Dartford they had a Woolworths with a huge basement. Great toy department I remember. Once when the Darent overflowed there were large fish swimming around in there. 

Edited by Onoff
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Woah, lets back up that horse.

 

Current 8’ x 6’ shed is sat on a 4” x 2” frame supported on 6 short 4” x 4” fence posts, post-creted in the ground. This was cheap and easiest for me to do.

 

I am looking to build something approx 20sq m. Again, to make it cheap and easy for me to do, I was planning on an insulated wooden base frame with pads/post. Then stick-building a basic insulated timber frame then wrapping and cladding. Optimistically I think this is within my capabilities (if not my current knowledge). Internals wise, I haven’t decided but would possibly plasterboard, if only for fire protection. But I am less concerned about the consequences for this than the overall structure.

 

If such a building were to flood, just how bad would it be? Would solid insulation be ok to leave? 

 

Is timber frame completely inappropriate? Will I have to dig foundations and pour a slab for this instead, maybe even masonry upto a certain height? (This would bring an unnecessary level of cost and complication)

 

what happens when a timber timber frame house floods? Do they rip out the wall insulation?

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EPS insulation would probably survive a dunking. the issue would be what sort of water.  Lovely clean rainwater, happy days. Something a bit pongy overflowing from next doors septic tank or coming up out of a sewer and not so happy days.

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19 minutes ago, ProDave said:

EPS insulation would probably survive a dunking. the issue would be what sort of water.  Lovely clean rainwater, happy days. Something a bit pongy overflowing from next doors septic tank or coming up out of a sewer and not so happy days.

 

Not many septic tanks in suburbia but no guarantees as to how 'clean' the water will be.  

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