Concrete planks floor C1650

[kat7t]

We are in the process of purchasing a house C1650. My husband has had a close look at the floor, and whilst there is a cellar with an arched ceiling the floors to the ground floor seem to be cement 'planks'. As you can see this is most definately not our field of expertise and we do not know if this has the same potential as concrete flooring causing damp. I have read that concrete floors can cause serious issues with damp, though currently there is no sign of damp in the property.
I'm really looking to understand if its not damp now, can it become damp in the future?
If it does become damp what can be done to correct the issue if the damp is caused by the concrete floor (assuming that the most expensive option is to pull up the concrete floor i'm hoping there would be alternative cheaper options?)
And obviously I'm not sure if these concrete 'planks' are the same as concrete floors, and therefore wonder if they have the potential to cause the same damp issues?
I've also read that if it has a concrete floor it will need a damp course, however some web sites state a damp course makes it worse.
Any advice/knowledge would be greatfully recieved. Thanks in advance.

 

[LadyArowana]

Hello and welcome. Just bumping this up the rankings as new members have their first few posts moderated and they can get lost further down the list. Cant really help with your dilemma, but tend to think if it's OK at the moment and has been in place for a while then it may happily stay that way.

 

[Keithj]

I'm no expert, but I would have thought that with air both sides of the concrete the problems should be few.

 

[88v8]

Never heard of this in a Period house, but yes it's a well-known technique in more modern builds.
http://www.spanwright.co.uk/prestressed-flooring

Perhaps there was a suspended timber floor that rotted?

It does suggest some fairly major reconstruction at some point, which I would want to look into for fear of what else might have been done. I would definitely suggest a specialist 'old building' surveyor before you commit.
The work was, I would guess, fairly recent, and if the house is listed it would have needed Listed Buildings Consent as it is not a 'like for like' replacement. You need to look into that as well.

Anyway, to answer your question, concrete causes damp when it is combined with installation of a damp-proof membrane, because the membrane prevents evaporation of damp from under the floor and pushes the damp to the perimeter where it climbs up the walls.
So if there is no dpm under your floor, it is unlikely that the concrete would cause damp problem.

However, if you want to get under the floor for cabling or plumbing, you have to take up a whole plank, you can't simply cut holes in it because that could cut the stressing tendons. Just an observation.

Ivor

 

[Feltwell]

Pictures would be good.

For someone to go to the hassle of retro-fitting pre-stressed concrete flooring in an old building seems very unlikely to me. "Block and Beam" - where upside-down T shaped beams are laid with "breeze blocks" in between them - are common in modern housing, I built my garage floor with these, but again I can't see anyone wanting to retro-fit them. There's a first for everything though!

Your surveyor should be able to tell you what you've got.

 

[MatthewC]

The work was, I would guess, fairly recent, and if the house is listed it would have needed Listed Buildings Consent as it is not a 'like for like' replacement. You need to look into that as well.

If your council has a decent website you should be able to find all the previous applications relating to your house, so have a good look at those and see if they cover it. I would NOT ask the CO about this question without considerable thought as to the possible consequences!!

(A lesson I learned in the RAF: "Never ask a question to which you might not want to hear the answer.")

Matthew

 

[88v8]

For someone to go to the hassle of retro-fitting pre-stressed concrete flooring in an old building seems very unlikely to me. "Block and Beam" - where upside-down T shaped beams are laid with "breeze blocks" in between them - are common in modern housing, I built my garage floor with these, but again I can't see anyone wanting to retro-fit them. There's a first for everything though!

Was racking my brains to think of these....
http://www.rackhamhousefloors.co.uk/products/beam-and-block.php
which I was recommended to use with minipiles to build my garage floor but didn't.

Thinking about it in the context of a Period house, perhaps this methodology has something to commend it, if one wants a solid floor. Less mass to install, no damp transmission into the walls, probably cheaper than limecrete, and more 'reversible'.

Not sure what CO would think, mind you.

Ivor