Integral Garage conversion

[Andy Velcro]

Hi

I am about to convert my garage to a room and have a few questions. When I have the garage opening bricked up will I need to dig a foundation? From what I can see the garage floor is made from the same slab as the rest of the house (although slightly lower). Is this slab suitable to build up from? Also does anyone have any pro's and con's on what type of floor to put down? I'm not sure what's best, insulation with boards ontop, timbers with insulation between or insulation with a screed etc.

Any tips would appreciated.

 

[flameport]

When I have the garage opening bricked up will I need to dig a foundation?

Probably not, although you will have to find out how thick the slab actually is. Will the existing opening be changed to a window with brickwork below?

Also does anyone have any pro's and con's on what type of floor to put down? I'm not sure what's best, insulation with boards ontop, timbers with insulation between or insulation with a screed etc.

What is the height difference between the garage slab and finished floor level in the house?

 

[Andy Velcro]

Hi

Yes it will be filled in with a few courses of bricks and a window. I think the difference in floor height is around 100mm. I will measure exactly and post. The chipboard on insulation baffles me slightly, I can't imagine the insulation standing the test of time, although I haven't seen the product yet.

Ta

 

[Jackthebiscuit]

How old is the property?

But given the property was built on a slab, you should be fine with the existing foundations, especially if the garage threshold is in good condition. If it has withstood/designed for vehicles access, then in reality you are not adding more weight, just a different type of weight, where the new load is spread over the threshold of the garage, rather than vehicle weight, where the load is more intense to a much smaller area via the tyres. Plus, if the existing lintel over the garage door is being retained, then even less cause for concern.

My preferred floor would be insulation and boards. If nothing else, it's nicer to walk on, and more 'forgiving', especially for the very young and the elderly.

.

 

[Andy Velcro]

The property is 4 years old. I take your point about the floor being able to withstand the weight of a car, ill mention that to planning. How tough is the insulation if you can lay chipboard straight ontop? If I was to use celotex or kingspan what are the model numbers of the boards.

Ta

 

[freddiemercurystwin]

Given that your house is only 4 years old the chances are very high that there will be a foundation there already (cheaper and quicker for developers to just run the trench/footing through rather than stopping it (although no guarantee there's a wall connecting the found to the underside of the slab). It'll probably be OK if there wasn't one tbh. Just check if your BCO will be happy before you build your wall.

Regarding floor make-up plywood would be a better choice either 18 or 22 T&G. Don't even consider chipboard if you want to tile any areas. Tiled areas should have WBP plywood beneath. The insulation would then be something like 75mm Celotex GA4000 depending upon final floor finishes/levels. http://www.insulationexpress.co.uk/documents/GA4000 Product Datasheet.pdf again confirm your BCO is happy before you buy it.

BTW if not already done so, it may be prudent to check that you retain Permitted Development rights to do a garage conversion, its not that uncommon nowadays for conversions to be excluded from PD rights for new builds.

 

[simonjay]

How old is the property?

But given the property was built on a slab, you should be fine with the existing foundations, especially if the garage threshold is in good condition. If it has withstood/designed for vehicles access, then in reality you are not adding more weight, just a different type of weight, where the new load is spread over the threshold of the garage, rather than vehicle weight, where the load is more intense to a much smaller area via the tyres. Plus, if the existing lintel over the garage door is being retained, then even less cause for concern.

My preferred floor would be insulation and boards. If nothing else, it's nicer to walk on, and more 'forgiving', especially for the very young and the elderly.

.

In newbuilds with boards over insulation, heavy wear areas have been found to dip slightly over time, which eventually leads to the chipboard breaking down and / or squeaking. Typically, areas around doorways etc. The method seems to be primarily a way of reducing build cost.
However, should be OK for 10 years or so
And it does lead to a warm feeling floor.
Simon.

 

[^woody^]

If the house is only four years old, then you may need to check that permitted development rights have not been removed, and that there is no planning condition requiring the garage to be kept as a garage

Although the slab edge may be able to take the load a of a wall, there is a risk of the edge shearing due to building close to the edge, or cracking along the inner line of the cavity wall

So, build the inner wall out of a timber frame and either span a tray lintel across the brick just above the floor, or build in some bed reinforcement every third course of brick and this will need to lap into the existing wall reveals

 

[noseall]

build in some bed reinforcement every third course of brick and this will need to lap into the existing wall reveals

Good old bricktor.

 

[geraint]

How old is the property?

But given the property was built on a slab, you should be fine with the existing foundations, especially if the garage threshold is in good condition. If it has withstood/designed for vehicles access, then in reality you are not adding more weight, just a different type of weight, where the new load is spread over the threshold of the garage, rather than vehicle weight, where the load is more intense to a much smaller area via the tyres. Plus, if the existing lintel over the garage door is being retained, then even less cause for concern.

My preferred floor would be insulation and boards. If nothing else, it's nicer to walk on, and more 'forgiving', especially for the very young and the elderly.

.

In newbuilds with boards over insulation, heavy wear areas have been found to dip slightly over time, which eventually leads to the chipboard breaking down and / or squeaking. Typically, areas around doorways etc. The method seems to be primarily a way of reducing build cost.
However, should be OK for 10 years or so
And it does lead to a warm feeling floor.
Simon.

That reminds me of someone that told me. what a lovely restaurant..... but the food is ****e....

 

[Andy Velcro]

Hi all

From what I can see in the garage(I haven't knocked through yet) the floor in the house is about 60mm higher than the garage. Although what I can see (which is wrapped in a dpm) may not be the top layer I suppose. I've checked with planning and I do need permission due to parking I believe. What are your thoughts on the way forward regarding planning and regs? Should I put in for full planning or inform planning and building control separately. I'm finding it all a bit of a mine field, I wish I had the cash to just let someone get on with it.

Ta

 

[^woody^]

Building regulations and planning are separate, so you have no choice but to get approval from each separately.

But regarding planning, if you have nowhere else to park a car on your land, then an application will most likely be rejected

 

[Andy Velcro]

I also have a 2 car driveway but in some cases the highways department have demanded a third!!

 

[^woody^]

Then you will need to dig some of the grass up

 

[Jackthebiscuit]

Then you will need to dig some of the grass up

About six months ago I was at a meeting at the London Borough of Brent and they were saying that they were cutting back on giving permission for householders to do this. They thought that too much garden space was being lost to car parking.

But I do wonder if the real reason is that they just want more cars parked on the road, especially in areas where they have restricted or 'permit parking' only. So they can charge residence a parking permit fee, or a 'pay and display' fee, and of course issue penalties for those who err.