Building Regulations and interior wall renovation.

[Skipperlance]

Walls and Regs....

We have a 1900 Victorian house with solid brick and stone walls with lime plasterwork which although is okay would benefit from re-skim.

The question is whether or not Building Control will, require the addition of insulation if we skimmed as a change in the thermal element of the wall. Existing plaster to be repaired where required and not completely removed.

There seems to be a great deal of confusion regarding this subject.......any pointers would be gratefully accepted.

Thanks in advance..........

 

[Richard C]

From what you’ve said, you’re not changing a thermal element just repairing one & it only applies to external walls. Removing/changing more than 24% is the magic figure & even then it’s not straight forward as you can trade off by improving the thermal efficiency of the building in other areas. LABC will only know if you tell them & why would you do that unless you are doing extensive work, just make sure you don’t get caught out if you have a BC expecting other notifyable work which is what usually happens.

Be careful what you repair with; if it’s lime render/plaster you cant use conventional render & gypsum plaster. If you haven’t done so already have a look through the Plastering forum, there has been a thread only last week & there are at least two others linked in one of my posts. You will also find advice rearding what materials/methods to use.

 

[Skipperlance]

Hi Richard and thanks for the reply.

Building control will be involved in other works on the house.
The walls are external.
I was lead to believe that the 24% rule applies to each wall...........to which I will be re-covering (but only with a skim coating) 100%.

Lance

 

[Richard C]

The 24% only applies to a thermal element; interior walls are not thermal elements. I've never personally had this problem, only know of others that have & each case seems to have been interpreted differently by the BI involved. I would think it’s really the base coat that constitutes the thermal element, so replacing the skim by 100% wouldn’t be a factor; it’s how much of the wall you strip back to brick. I’d also be more inclined to think it would apply to the thermal element in each room which could be more than one wall, depends.

There is also the possibility that the plaster is worse than you think & you could end up stripping the lot. Sometimes it’s better to do the job properly but then, as I said, you’re going to be involved with special materials unless you provide a damp membrane, insulation & re-board which you may be forced to do anyway if LABC get involved. Unless you can complete the plastering work after completion & sign off of the other inspected works your doing so it won’t get spotted by BI, you might be wise to talk to LABC & get their view.

 

[^woody^]

Skimming, and gradual (ie patch) repairs don't count

Also, what people often forget about this 25% lark is that the regs state that "reasonable provision shall be made for the conservation of of fuel and power" and go on to mention feasibility and practicality along with technical constraints, and then mention a financial benefit over a 15 year payback period

The upshot is that there are many viable reasons as to why the thermal element does not have to be upgraded. It is not an automatic requirement to insulate

 

[jabuzzard]

Coming at it from the other direction, given that you are going to be skimming the whole wall anyway, it might be a good idea for the future comfort of the room to strip it back and insulate regardless of whether it is necessary or not, as now is the time to do it.

Fuel prices are only going one way in the long term, but even if you never make you money back in fuel savings, being able to easily heat the room to a comfortable temperature when it is cold outside has a value all of it's own.