Farmhouse Floor Replacement

[tegwen]

Hi

We have recently purchased a carstone and brick farmhouse circa 1840. The property was suffering from extensive rising damp throughout the ground floor. The reason for this we believe was the cement based concrete floors that were installed during a 1950's modernisation. All walls have now been took back to brick, ad all of the offending floor has been broken up and removed. The problem is I am unsure as to the best replacement options for both floors and walls.
any advice or guidance would be greatly appreciated.

Regards

Jason and Debbie

 

[Gervase]

The best floor for that sort of building would be a limecrete floor without a plastic membrane. That would allow the whole area to breathe and - provided your outside soil levels were below floor level - the whole building would be dry and snug. As for the walls, get rid of any cement pointing or render on the outside and replace with lime, and any cement or gypsum plaster on the inside should be replace with lime plaster.
But that's a counsel of perfection. Sort out the outside soil levels, drainage and guttering and you may find that everything's fine. if not, put in a limecrete floor. If (and it's a big 'if') you've still got damp trouble, sort out the walls.
But, as with all things to do with houses, take your time. It can take a couple of months - or even longer - for changes in moisture levels to get to the point where they're noticeable, particularly at this time of year when moist air and cold surfaces encourage condensation.

 

[tegwen]

Hi Gervase

Thanks for your advice on the floor and walls, in your experience would you say laying a limecrete floor is something a well seasoned diy'er could tackle. I would be laying an area of approx 60 sq m over three rooms all interconnecting.

Cheers

Jason

 

[MdB]

60m^2 dug to a depth of 300mm is roughly 30 to 40 tonnes of material to both remove and replace. Just so you know in advance (you can get mini diggers that will go through doorways to help with this). Limecrete floors with insulation are around 400mm deep if I remember correctly so you may need to increase this figure.

Oh and if you are doing more than 25% of the floor (which it sounds like you are) then you will need to 100% of the floor area to keep building control happy. This means you won't be able to leave the awkward downstairs loo but have to refloor the whole house. (Seems a rather strange rule to me, but there you go...)

 

[Matt Green]

The property was suffering from extensive rising damp throughout the ground floor. The reason for this we believe was the cement based concrete floors that were installed during a 1950's modernisation.

Are the outside ground levels at least 6" below interior floor height? High ground levels really are the most common cause of 'rising damp'.

Matt

 

[Penners]

Oh and if you are doing more than 25% of the floor (which it sounds like you are) then you will need to 100% of the floor area to keep building control happy.

Can you just confirm that, MdB? If you're proposing to dig up and replace more than 25% of your ground floor, then building control will require you to do the entire floor throughout the house?

Is that right? Do you have any idea why?

 

[MdB]

Can you just confirm that, MdB? If you're proposing to dig up and replace more than 25% of your ground floor, then building control will require you to do the entire floor throughout the house?

Is that right? Do you have any idea why?

I submitted plans to building control to replace approx 50% of the floor in the house. The following came back:

L1B - As work to the existing floor amounts to greater than 25% of the existing floor area, the entire ground floor will need upgrading accordingly, please provide details.

I never bothered finding out why as we were planning to do the rest of the floor anyway.

Just had a look at approved document L1B. Section 54 states the following:

Renovation of Thermal Elements
54 Where a thermal element is being renovated reasonable provision in most cases would be to achieve the standards set out in column(b) of Table 5. Where the works apply to less than 25% of the surface area however reasonable provision could be to do nothing to improve energy performance.

I think it is saying that if you work on more than 25% of the floor then the entire floor has to meet the current standards for U values (0.25W/m^2K for floors). Its not very clear to me though and I am sure that different building control people look at it in different ways.

 

[Ian Bond]

I'm just thankful that I only need to repair 24.99999 percent of my part flagstone, part timber floors in that case.

I suppose I could do it in several stages!!!!

In practice, if you are digging up the entire floor (to remove concrete, install heating and then limecrete) then it does make sense to insulate.