Identifying Cavity Wall

[Richard Conway]

Hi all,

Having just about survived the winter in our chilly end terraced we are considering what we can do over the summer to make sure we don't suffer as badly next year. New loft insulation is top of the list and possibly a new boiler as the existing one seems underpowered (have yet to do the calcs - but it doesn't make a dint when on full pelt all day long).

I have always assumed that our the house doesn't have cavity walls as it was built in 1905 and I didn't think they were really used until quite a few years after that - but it occurred to me this morning that the brickwork doesn't have any bricks end-on (IYSWIM) that would usually identify it as a solid wall. Is it as simple as this though, or could it still be a solid wall?

If there is still doubt, does anyone have any tips on how I can find out for sure?

Cheers.

Richard Conway.

[Dave Fawthrop]

|Hi all, | |Having just about survived the winter in our chilly end terraced we are |considering what we can do over the summer to make sure we don't suffer |as badly next year. New loft insulation is top of the list and possibly |a new boiler as the existing one seems underpowered (have yet to do the |calcs - but it doesn't make a dint when on full pelt all day long). | |I have always assumed that our the house doesn't have cavity walls as it |was built in 1905 and I didn't think they were really used until quite a |few years after that - but it occurred to me this morning that the |brickwork doesn't have any bricks end-on (IYSWIM) that would usually |identify it as a solid wall. Is it as simple as this though, or could |it still be a solid wall?

Yes.

|If there is still doubt, does anyone have any tips on how I can find out |for sure?

A long masonry drill, through the outside ?leaf?. Drill until you hit nothing or until it emerges inside the house.

[Ian Stirling]

There is a trivial way, if you own a SDS drill, and a long enough drillbit.

[Colin Wilson]

Get a longish drill bit, and go to a depth of just over a brick (plus plaster on the inside) ?

[Chris Bacon]

There are a few early ones around.. 1910-ish is when they became more popular.

It's almost certainly a cavity wall, then.

Measure how thick it is, and compare it to the length of a brick, allowing for 1" of plaster on the inside. Look for the prescence of air-bricks or cast-iron grilles around the bottom of the wall (just above the damp-proof course).

[meow2222]

Cavity walls date back to the 1800s. The notion they werent used till the 30s is a popular myth.

The simplest test is to measure the wall thickness. This plus knowing the way the bricks are laid will tell you. You should also drill a hole through just the interior plaster to determine exactly where the brick is, and whether is it in fact brick. The question is not just whether it has a cavity, but how big it is, and whether the inner skin is brick, block or stone. Rough stone inner leaf brick walls are not suitable for cwi, ditto half inch cavities in brick, which is the most common early cavity size. Ratbond is also not suitable but you dont have that.

You'll need to test each wall, it would be quite wrong to assume all walls are the same construction. Mix and match was normal practice a century ago, with sometimes even one wall using more than one type of construction.

NT

[Dave]

I would drill from the inside to outside. You are never sure just where the drill will end up. Also checking for cables will be that much easier.

Dave

[Phil L]

Measure one of the exterior bricks at a corner (usually around 4.5 inches). Take a long masonry bit and mark off at 4.5 inches with tape. Drill at least 2 or 3 holes (in the mortar joints) on each elevation. If the drill doesn't noticably jolt forward on each hole, you have no cavity. If you are 'unsure' or think there's a 'bit' of a cavity, forget it, it needs to be at least 50mm (2 inches) for injected fibreglass to be gauranteed, but more importantly, to work effectively...you can feel around inside with a bent coat hanger wire.

[Chris Bacon]

They may do, but they would have been an extreme rarity then.

They started general use in the early 20th. century, but weren't generally used 'till later.

You don't need to drill holes to find that out.

Rubbish. You spout this every time. That there is a small gap between some bricks, by no means all, in a "solid" wall is due to the size of the bricks. Solid walls were not intended to be cavity walls, and indeed are useless as such, as headers pass through the wall, and the bricks are linked by large dollops of lime mortar.

There is no such thing as "ratbond". Rat trap is found on cheap buildings, as it is inferior to most other brickwork.

[Chris Bacon]

There's no need to drill through the wall, and drilling from in to out side is asking for a flippin' great crater to disfigure your brickwork. See many TV ariel installers bodges (presumably *not* Bill Wright).

[Andrew Mawson]

usually

[Chris Bacon]

Wow! That'll give Nige something to gossip about on "Periodproperty"! Fascinating information. Is there an on-line reference site?

[Phil L]

The Romans had cavity walls too, and fires lit underneath their marble floors (and tended 24/7 by slaves) heated their houses and the cavities were used as chimneys, keeping the walls dry too, mind you, this is back when slaves were cheap.

[Dave]

SDS drill? I'll bet. I was thinking about the old fashioned masonry drill.

Dave

[meow2222]

There are a lot of rarities about then :)

How do you propose finding out what the inner leaf is made of?

So the existence of one wall type precludes another?

Rat-trap bond, chinese bond, etc, if we're being pedantic.

The claims of inferiority seem hard to justify, given that its superior in every way to single skin, which is also common on old builds, and is a bridged 4" cavity construction, thus one of the better types for insulation.

NT

[Dave Fawthrop]

|Chris Bacon wrote: |> Dave wrote: |> |>> Dave Fawthrop wrote: |>>

|>>> A long masonry drill, through the outside ?leaf?. Drill until you hit |>>> nothing or until it emerges inside the house. |>>

|>>

|>> I would drill from the inside to outside. You are never sure just |>> where the drill will end up. Also checking for cables will be that |>> much easier. |> |> |> There's no need to drill through the wall, and drilling from in to out |> side is asking for a flippin' great crater to disfigure your brickwork. |> See many TV ariel installers bodges (presumably *not* Bill Wright). | |SDS drill? I'll bet. |I was thinking about the old fashioned masonry drill.

Holes which I drill with an SDS come out nice and round, and the right diameter, from the surface in. I am always careful when using powerful tools, and only lean on them when the job demands it.

[Chris Bacon]

Do you mean "there may have been a few in 1899"? If you really mean from the 1800s, then where are all these houses? Examples, please.

[meow2222]

I wonder if they might be few and far between where you live. Round here they're not rare at all.

NT

[Chris Bacon]

Where are they, then? Specific examples would be useful. What age are the houses? 1800? 1845? 1899? 1910?

Note, if you happen to live an oldish house with cavity walls next to two others similar, it does not necessarily mean that they're "not rare at all".

[meow2222]

omg, I had no idea! I'm only a 4 year old, so you can see why I cant figure out what 'rare' means.

I dont mind sensible convos, but not silly stuff.

NT