Suspended timber floor to Limecrete or something else?

[a twig]

Yes you may well be right, it's not something I was aware of. I would expect to see it above the airbrick though. How old is the house again, early 20th century? You could do a bit of exploring by scraping away a bit of mortar. It's easily replaced.

Was going to say the same thing, very gently chip some mortar away and see if you find any slate which would indicate a DPC.

Air brick could have been added later in the “wrong” place, or it could have been a 1930s apprentice not quite getting the brickwork right

Peering at the air brick there might be some slate above it where someone has tried to continue the DPC up and over it. Had the same on this place where the airbricks were in the course above the slate DPC and the vertical joints and horizontal joint around the airbrick had been packed with slate to try and continue the DPC up over and back down again.

Either that or the mortar is a different colour indicating that it is a later addition.

 

[Aaron83]

Was going to say the same thing, very gently chip some mortar away and see if you find any slate which would indicate a DPC.

Air brick could have been added later in the “wrong” place, or it could have been a 1930s apprentice not quite getting the brickwork right

Peering at the air brick there might be some slate above it where someone has tried to continue the DPC up and over it. Had the same on this place where the airbricks were in the course above the slate DPC and the vertical joints and horizontal joint around the airbrick had been packed with slate to try and continue the DPC up over and back down again.

Either that or the mortar is a different colour indicating that it is a later addition.

Well it's been a while.
@Lacan07 @a twig @Kearn I was unable to get a builder to come over and check if we had a DPC, but did manage to get SOME info - my brother in-law confirmed his house (same age, but different design) has a slate DPC - AND, destroy a section of our brick work, in the search of this illusive DPC .

Basically, I couldn't chip any of the mortar away using a chisel (it was too hard, in both senses), so took an angle grinder to it and, well, you can see the damage I've done (don't laugh ).
Even though it seems to have a dark grey/black material a few mm's down, I can't be sure it is a DPC (can you/anyone?).

I've also included pics at the back of our home with an even higher ground level (10-20mm below suspected DPC), and (to my untrained eye) it seems that it could be a DPC as the brickwork/mortar below the line is in very bad shape, whilst the brickwork above it (with the horrible red paint) seems much better.
Is this the proof I need to confirm it being a DPC???


Many thanks all

 

[Kearn]

If you’re thinking that fatter line of cement mortar is hiding a DPC, then I’d be looking in through the airbrick - much easier to remove or get a borescope from from Amazon and poke the camera through…

 

[Aaron83]

If you’re thinking that fatter line of cement mortar is hiding a DPC, then I’d be looking in through the airbrick - much easier to remove or get a borescope from from Amazon and poke the camera through…

Thanks for the tip @Kearn , I may have to do that if I still have reservations, but....

I've actually just had a chat with a nearby neighbour with an identical house, who I remembered today is a retired architect. Both good and bad news for us from the chat:

The good is that he's certain our houses, built in 1929, have slate DPC's. Due to the fact he noticed the sleeper walls having slate on them when taking a section of floor up. Hence his thinking is, why wouldn't the end of the timber be also sat on slate, and if it wasn't, it would be rotten.

The bad news is, with the floor joists sitting on the DPC, it means our internal floor level is roughly 2 bricks higher than the DPC. Hence think that may cause issues with bridging if/when we go to install a solid floor.
Does anyone know if a good way around this?

Many thanks to all again.

 

[Stevers]

Does anyone know if a good way around this?

Don't install a solid floor?

 

[Aaron83]

Don't install a solid floor?

I'd much rather have the solid floor for both insulation & thermal storage(of UFH), but is there a way of having both without a solid floor?

Thanks.

 

[Stevers]

Your home was designed to have a suspended timber floor. The degree of insulation and thermal mass required to provide UFH in such a building makes this a risky, messy and expensive project to gain what is often found to be a dubious benefit. When contemplating such an expense I like to consider what else all that treasure could achieve - see also luxury cars, exotic holidays and big weddings!

 

[a twig]

I honestly couldn’t agree more with @Stevers - finding a DPC where you thought there was none is a big win and just making sure your suspended floor is in good nick with large gaps filled and a decent underlay will help with the warmth.

There are UFH products for suspended floors if you are desperate for warm toes but it will by definition be less efficient as you will lose heat down into the void even with your best efforts to limit that and whacking insulation in between the joists can cause its own problems - you’d be better off ££ wise with radiators.

 

[Stevers]

It might be an option to drop the suspended floor to leave room for insulation. Thermal mass is not really your friend for UFH as it introduces lag which would not normally be a good thing unless you're attempting to make somewhat inefficent use of cheap rate electricity.

Philosophically a problem with big spends is that they're very tax inefficient. Your spend can incur VAT on nearly everything, income tax and NI for the labourers, craftsmen and owners/admin. There will be rates for any business property, and vehicle and fuel duty for any transport used, not to mention Corporation Tax on any profit. All paid for out of your quite possibly heavily taxed income. If you borrow to fund all this taxation, then that's worse!

I quickly learned that money not spent, was money I didn't have to earn, and very heavily geared in my favour at that! Much better to pay mortgages down, or put money into pension or ISA for some future unspecified joy.

 

[Lacan07]

Aaron already knows my views on his solid floor plans which largely align with Stevers and Twig. His original plan for limecrete would mitigate the risk to the surrounding walls somewhat but to what degree would be my argument.

As I've said before I'd be amazed if this house didn't have a DPC, although one would expect to find it just above the air bricks. By and large however this house is sound and dry from what I can remember and Aaron has already done some great work removing the horrible render.

 

[Aaron83]

Many thanks for your help/thoughts guys @Stevers @a twig @Lacan07 . It's all much appreciated.

I never thought I'd say this, but I am coming around to NOT installing a solid floor, but really feel this is an opportunity to insulate it and (maybe) add UFH as the plan is to one day replace our boiler with an ASHP.

What's everyone's thought on a system like this*, then (somehow**) adding UFH on top?

*
(Picture attached) https://www.eco-home-essentials.co.uk/underfloor-insulation.html

**
Can you tell flooring isn't my forte