concrete slabs

mjffey

Why do they, here in Ireland, put a concrete slab around houses? I've never seen this where I come from.
In my opnion it's not only ugly to see, but it also prevends water from going straight into the soil away from the walls. Instead the concrete stays wet and so does the wall as waterdrops splash against the walls (and make them dirty too)

Why????????

Mellor

So that you can walk around the house and garden without stepping into the muck and dragging it into the house.

mjffey

Really? You're joking aren't you.

Kashkai

No he's not joking. Seems daft to me to have soil right up against a house. I know we have damp proof courses to keep dampness out of the house but having muck up to the wall doesn't seem like a good idea.

My mate bought a house that didn't have a slab/path around his house and when it rained, it was muck that got splashed up on the house and since it was painted a light shade of cream, it looked awful.

Alun

Well, if you're that concerned about muck splashing against the walls, you can put in your own paving around the house which will look a lot nicer than a bland strip of concrete.

A few people around my estate have done just that and had theirs removed and replaced with paving or gravel which looks a lot nicer IMO.

Macy

mjffey wrote:

In my opnion it's not only ugly to see, but it also prevends water from going straight into the soil away from the walls. Instead the concrete stays wet and so does the wall as waterdrops splash against the walls (and make them dirty too)

Surely the splashing is an issue whatever the surface? Assuming the paving concrete/ paving is properly laid, then water isn't sitting against the walls and will infact be run off further away from the house?

Kashkai

Alun wrote:

Well, if you're that concerned about muck splashing against the walls, you can put in your own paving around the house which will look a lot nicer than a bland strip of concrete.

A few people around my estate have done just that and had theirs removed and replaced with paving or gravel which looks a lot nicer IMO.

The OP was wondering why concrete is put around houses. I never said I thought it was nice - it's usually covered in moss.

Putting in your own cobblelock/gravel is a nicer idea and one I'll be using to finish off the area around my house once the builders go away (some day soon I hope!!!):D

muffler

mjffey wrote:

Why do they, here in Ireland, put a concrete slab around houses? I've never seen this where I come from.
In my opnion it's not only ugly to see, but it also prevends water from going straight into the soil away from the walls. Instead the concrete stays wet and so does the wall as waterdrops splash against the walls (and make them dirty too)

Why????????

I think Mellor summed it up nicely.

Now what would you have around your house mjffey?

Or do you prefer walking around in the muck with a pair of wellies

Viking House

About 20% of the heat escapes through the foundations of a house and a footpath is a big contribitor as it helps to keep the foundations damp.

We always put a drain around the outside of the foundations for this reason and fill it with LWA or gravel, we use a membrane between the clay and the LWA/gravel to stop the two mixing.

Any time we removed footpaths we found a lot of insects underneath because of the damp conditions.

Johnniep

Viking House wrote:

About 20% of the heat escapes through the foundations of a house

Is this true Viking House???:eek: I realise there is a cold-bridge between footings and external walls but would never have imagined it would be that high. Thats good to know!!!

Better get looking for a better detail then.

J.

muffler

Viking House wrote:

About 20% of the heat escapes through the foundations of a house

Nonesence. Im surprised you had the neck to even suggest that

Sonnenblumen

mjffey wrote:

Why do they, here in Ireland, put a concrete slab around houses? I've never seen this where I come from.
In my opnion it's not only ugly to see, but it also prevends water from going straight into the soil away from the walls. Instead the concrete stays wet and so does the wall as waterdrops splash against the walls (and make them dirty too)

Why????????

Basically done because its fast cheap and mostly nasty finish. But there are increasing numbers of people choosing alternative materials to adjoin houses. We typically recommend river cobble and/planting margin.

The truth is most builders know little about garden aesthetics and where there is no conflict with access, double band perimeter planting with inner access path is a superb and much more sympathetic finish to housing at ground level. Like most things all it takes is a little imagination and the willingness to do it properly.

Recommend it over concrete or any other hard surface for that matter.
Also if done properly it is a very simple but helpful environmental way to utilise run-off water, ie divert to planting areas.

Mellor

Viking House wrote:

About 20% of the heat escapes through the foundations of a house

Maybe in an uninsulated house, but in standard level of construction i'd say its closer to 10%. And thats for the whole floor and not just the foundations.

muffler

Viking House wrote:

Any time we removed footpaths we found a lot of insects underneath because of the damp conditions.

And you expected to find ????????????????? ............... free range hens

mjffey

muffler wrote:

I think Mellor summed it up nicely.

Now what would you have around your house mjffey?

Or do you prefer walking around in the muck with a pair of wellies

I'm from the Netherlands and there you have the soil right up against your house. You will have a footpath to every outdoor in the house. Most of the time laid from bricks/pebbles/flagstones. As is the case with driveways. No concrete or tarmac.
For the rest you put plants around your house.

How often do you walk that close to your walls that you need concrete all around the place?


Now I know that the concrete slab is a kind of tradition and has no purpose at all, we won't have it around our new to build extension, and maybe even have it removed around the existing house. It looks so much nicer without it. I will put some nice plants instead.

And for the muddy wellies..... we use doormats......:D

Viking House

Hi Muffler

You are the moderator right!!
Does that give you a free hand on sarcastic remarks?

If you have your house insulated well and there is one weak spot i.e. the foundations where the wall insulation fails to meet up with the floor insulation which is 99% of the time in Ireland even in timber frame houses, then you can loose well over 50% of your houses heat through these areas.
Its like having one leg outside the bedclothes on a frosty night.

When your foundations are damp then this makes the situation worse its like having wet clothes on a cold day.

If you have a slow puncture in a biycycle wheel then 100% of the air will leak out through a pinhole just like the heat in your house.

muffler

mjffey wrote:

And for the muddy wellies..... we use doormats......:D

I never knew that people in Holland wore doormats

Seriously though I can see your point alright. It does indeed give a much more refreshing view to a house to have the lawn or flower beds up close to the walls.

The slabs are used primarily for surface water run -off and to keep the area around the house free from muck and wet if people are going to be using it for walking on. Most rural houses use the back door as the primary entry point to the house so unless they have a driveway around the side and back they will walk from the front of the house to the back.

Likewise when kids are out playing or coming in from school etc they will also use the rear door on most occasions. I think in those instances you will see the reason for having concrete paving around the house not to mention the fact that it substantially cuts down the amount of moisture retention in the subsoil adjacent to external walls

muffler

Viking House wrote:

Hi Muffler

You are the moderator right!!
Does that give you a free hand on sarcastic remarks?

If you have your house insulated well and there is one weak spot i.e. the foundations where the wall insulation fails to meet up with the floor insulation which is 99% of the time in Ireland even in timber frame houses, then you can loose well over 50% of your houses heat through these areas.
Its like having one leg outside the bedclothes on a frosty night.

When your foundations are damp then this makes the situation worse its like having wet clothes on a cold day.

If you have a slow puncture in a biycycle wheel then 100% of the air will leak out through a pinhole just like the heat in your house.

Im a moderator alright (North West forum) but in here I am just Joe Soap.

Im not even going to comment on what you have posted as it defies logic.

Did anyone ever tell you that warm air rises?

mjffey

muffler wrote:

I never knew that people in Holland wore doormats

There's a lot you don't know about us.....

For the record: It's The Netherlands, not Holland. Holland is a County in The Netherlands just like Co. Mayo, Sligo etc. are in Ireland.

muffler

Thats amazing. I always thought that Holland and The Netherlands were one and the same just like Ireland/Eire.

Out of curiousity - at international football matches you would hear the fans chanting what sounds like "Holland" - what exactly are they chanting?

Apologies to mods for going a wee bit OT here but this is interesting

Viking House

One of my engineers did a 2 year theisis on Thermal Imaging and these are his findings.
I can show you the photos.

muffler

Findings??????? Where?

Mellor

Viking House wrote:

the foundations where the wall insulation fails to meet up with the floor insulation which is 99% of the time in Ireland even in timber frame houses, then you can loose well over 50% of your houses heat through these areas.

I would agree that the area you described is a weak point and there is a cold bridge about 100mm wide there in most houses.
But I think that 50% is alot on the high side. If you want to stand by that then so be it. But i'd be interested to hear where the other 50% goes.

Also, how does the use of either 100mm concrete here or the use of soil effect that junction. Infact soil has a higher average moisture content than concrete. And rain will pass through soil quicker than it will concrete.

When your foundations are damp then this makes the situation worse its like having wet clothes on a cold day.

When any external permiable surface of a house is wet heat will escape faster. If the earth under the house, (under both the foundations and the floor slab), is wet it will effect the heat loss. As wet soil is more conductive than dry. But once again I fail to see how having a concrete paving, as opposed to soil/flags/cobblelock/gravel has an effect on these.

Viking House

Hi Mellor

Here is my point, our aim is to build houses which require minimal heating and if we build/insulate a house to Passive levels and use a standard Irish type foundation then most of the heat will escape through the floors and foundations. We are using a new foundation detail that eliminates the cold bridge where the wall meets the floor.
The footings for the internal walls let heat into the ground under the house, this heat gets drawn out much quicker by damp foundations.

By removing the footpath and replacing it with a drain and gravel you are lowering the water table and keeping your foundations dryer, so you loose less heat.
http://www.paroc.com/channels/com/building+insulation/solutions/cellar/cellar+wall.asp

Mellor

Viking House wrote:

Hi Mellor

We are using a new foundation detail that eliminates the cold bridge where the wall meets the floor.


By removing the footpath and replacing it with a drain and gravel you are lowering the water table and keeping your foundations dryer, so you loose less heat.

I'd agree with what you are saying. And I also agree that a detail lie the one shown would improve proformance. I'd be interested to see the detail you use for a regular floor to slab as the one shown is for basements. I think I know how you do it. But not too sure. Looks very interesting though.

I never disagreed that a drain would improve the proformance, but my point is that you were a little unclear, you were saying that concrete paths are bad and gravel is better. But without the drain its the same. A detail like you shown without the drain, and just gravel thrown in would be no better than a path.

My point all along has been that concrete paths are no better in proformance terms than flagstones or gravel edging etc.

muffler

Yes indeed the detail shown is for a basement with a high abutting ground level.

Im at a loss to know how anyone who is apparantly in the house building trade can suggest this: a standard Irish type foundation then most of the heat will escape through the floors and foundations.

There is a small amount of heat loss through every component of a house but with standard building/insulation detailing it is both naive and foolish to make comments like the above

I dont know what Viking House is hoping to achieve by making such outlandish statements

CJhaughey

muffler wrote:

Yes indeed the detail shown is for a basement with a high abutting ground level.

Im at a loss to know how anyone who is apparantly in the house building trade can suggest this: a standard Irish type foundation then most of the heat will escape through the floors and foundations.

There is a small amount of heat loss through every component of a house but with standard building/insulation detailing it is both naive and foolish to make comments like the above

I dont know what Viking House is hoping to achieve by making such outlandish statements

You misquoted Viking house, what he said was

Viking House wrote:

]if we build/insulate a house to Passive levels and use a standard Irish type foundation then most of the heat will escape through the floors and foundations

I take this to mean that in a passive house build that the energy loss through the Wall and roof is so low that the main energy loss would be through the floorIF the standard type of Irish foundation was used.

muffler

CJhaughey wrote:

You misquoted Viking house, what he said was
I take this to mean that in a passive house build that the energy loss through the Wall and roof is so low that the main energy loss would be through the floorIF the standard type of Irish foundation was used.

I will let Viking House state his definition of "passive"

I will stand by my statement that its utter nonesence to suggest that most of the heat from a house is lost through foundations if the house is built in accordance with standard construction/insulation detailing.

CJhaughey

I am not speaking for Viking House,I am sure that he can do that well enough himself
but in EU terms
The criteria for a Passive House per m² living area:

* Max. 10 W/m² constant heating-load
* Max. 15 kWh/(m²a) annual space-heat requirement
* Max. 42 kWh/(m2a) annual total amount of active energy input
Max. 120 kWh/(m2a) total energy requirement for space-heating, domestic hot water and household appliances
and the defination is :
"Passive Houses are buildings which ensure a comfortable indoor climate in summer and in winter without needing a conventional heating system. To permit this, it is essential that the building's annual demand for space heating does not exceed 15 kWh/m2year.

You are quite entitled to stand by your statement.
However many people would suggest that standard construction/insulation detailing is woefully inadequate and that if you build to standard construction/insulation standards the bulk of your heat will of course not be lost through the foundations rather escape through the walls and roof.

Mellor

CJhaughey wrote:

You misquoted Viking house, what he said was
I take this to mean that in a passive house build that the energy loss through the Wall and roof is so low that the main energy loss would be through the floorIF the standard type of Irish foundation was used.

Actually what he said first was

Viking House wrote:

About 20% of the heat escapes through the foundations of a house

He didn't mention passive until his last post. Passive housing was never discussed, I was under the impression that we were discussing traditional irish construction and concrete paving.

Viking House

Hi Mellor,CJ and Muffler.

You are all right! I mentioned 20% in the first post because this figure was in my head from Scandinavian data and from the Thermal imaging results I recieved and I never mentioned Passive in my first post.
In the SEI website it states that this figure is 10%. Ok.

I don't want to argue about this anymore. Let's move on.

Mellor wrote:

but my point is that you were a little unclear, you were saying that concrete paths are bad and gravel is better. But without the drain its the same. A detail like you shown without the drain, and just gravel thrown in would be no better than a path.
My point all along has been that concrete paths are no better in proformance terms than flagstones or gravel edging etc.

Hi Mellor

My point is that the concrete path keeps more dampness around the foundations than gravel because it stops the ground from drying out even if there is no drain.
It gives the same effect as a sheet of polythene against the lower wall of your house, the wall is damp when you remove the polythene.

Regarding the cold bridge at floor slab level. I am working with a Sweedish engineer working in Ireland who is doing up a foundation detail based on Insulated Concrete formwork. But at the moment we are building our Poroton blocks and Timber frame 30cm below finished floor level and the insulation in the walls joins up with the insulation in the floor.