Does a Conservatory need Footings?

Frank99

I have had several quotes for a replacement Conservatory, the original Conservatory which my dad built with wooden frames is in need of replacing however, one of the quoters told me that the original concrete floor would need to be removed so new deep footing and foundation can be put in place. strangely however the larger more experienced companies who i received quotes from have told me that no footings would be required for a conservatory of this size or possibly just for the new walls.
I have no idea if my late father put footings in originally or not but no movement has ever occured that i know of, one company told me as the base is more than six inches thick we don't need to dig it up to put new footings in.
My concern is that as it costs a lot of money to get this done so i just want to make sure everything is done correctly with no chance of any future problems in years to come.
The quote is for: Lean-to Conservatory measuring: Width 5200 mm Depth 2000 mm Base area 10.400 sq.m and Dwarf Wall plus one Large Wall.
Does anybody know what the rules on this are, do i need a completely new foundation or not, the companies who say i don't need it are big players and the one who said i do is a local company however, the quotes are virtually identical on price.:mad:

Aylesbury_Duck

Link to the previous thread: https://forums.moneysavingexpert.com/discussion/5795481

I cannot see how anyone can really advise on whether you need new foundations, we simply do not have the information to work with. I would be concerned that the bigger companies are saying it is not needed just to get the business. It might be true, it might not be. Personally I would always go with a long-standing local firm based on word-of-mouth recommendations because their ongoing business depends upon happy customers. I had a local company build mine and the minor trouble I had to date was sorted promptly and effectively, even though it was built over three years ago.

Doozergirl

Conservatories need footings just as much as any extension does. Ground moves always and constantly - the weight pushing down onto it from a building actually has very little to do with the depth.

The purpose of a correctly designed footing is to find solid ground first - that is basically accepted by building control as being a minimum of 1 metre in ordinary conditions.

The problem with conservatory companies is that conservatories are exempt from building control. That is why they are cheaper than proper extensions - no one is watching. Hence little to no foundations.

Aylesbury_Duck

Yes, and the OP considered £12k to be expensive, expecting it to cost nearer to £6k. God knows what the quality would be like at that price.

Furts

Frank99 wrote: »

My concern is that as it costs a lot of money to get this done so i just want to make sure everything is done correctly with no chance of any future problems in years to come.
The quote is for: Lean-to Conservatory measuring: Width 5200 mm Depth 2000 mm Base area 10.400 sq.m and Dwarf Wall plus one Large Wall.
Does anybody know what the rules on this are, do i need a completely new foundation or not, the companies who say i don't need it are big players and the one who said i do is a local company however, the quotes are virtually identical on price.:mad:

The big companies will be snake oil and spiv companies out to fleece you and cut corners. A simple fact of life, so no point in commenting further here.

The local company, if decent, will be the one you should be talking to.

Of course you need foundations for a wall, all the more so when by your own admission it is a "large wall" Talk about the "bleedin obvious!" What happens if this wall then cracks, falls down and kills you because there are no foundations?

But there is far more than this to building a conservatory, from a new insulated floor, to dwarf wall specification, to stability of the large wall, to ... you get the idea. Which all round means you have matters back to front. You cannot have things "done correctly" if you do not have an appropriate design, an appropriate specification, and appropriate notions of quality versus price. This in turn means you cannot be achieving meaningful quotes - which is exactly what you are finding.

Sort out your deign, which includes a careful think about usable floor space, then get a Specification drawn up.

Frank99

Many thanks for all the comments :beer:, i know exactly what i want in terms of design but the problem was that i wanted one side wall very close to my garden shed, this led to some quotes claiming it was possible and others saying it was not.
I do believe all structures should have the correct foundations and that is why i have been asking for information on this;just to make sure.
One of my quoters has now agreed to give me a fully insulated base however, i'm no builder so i don't know if that means correct footings?
I am asking these questions because i don't want to regret it later!

Warwick_Hunt

Frank99 wrote: »

Many thanks for all the comments :beer:, i know exactly what i want in terms of design but the problem was that i wanted one side wall very close to my garden shed, this led to some quotes claiming it was possible and others saying it was not.
I do believe all structures should have the correct foundations and that is why i have been asking for information on this;just to make sure.
One of my quoters has now agreed to give me a fully insulated base however, i'm no builder so i don't know if that means correct footings?
I am asking these questions because i don't want to regret it later!

The insulated base and footings are two different things.

Warwick_Hunt

Frank99

Thanks for the picture, this is a real eye opener for me, i can see from this that this insulated floor would be incomplete without the concrete footings.
It seems that due to my lack of knowledge they are trying to trick me into thinking i was getting the footings.
I think they are to lazy to drill out the existing floor in order to do this but if a jobs worth doing, it's worth doing properly and i'm going to insist on the footings with all quotes.

Furts

Frank99 wrote: »

Thanks for the picture, this is a real eye opener for me, i can see from this that this insulated floor would be incomplete without the concrete footings.
It seems that due to my lack of knowledge they are trying to trick me into thinking i was getting the footings.
I think they are to lazy to drill out the existing floor in order to do this but if a jobs worth doing, it's worth doing properly and i'm going to insist on the footings with all quotes.

The diagram is a good indication of how things work. However it is flawed. The foundations, on the vast majority of conservatories, should be far deeper than shown. Factor this in when you are pondering. In addition the cavity and insulation should be upgraded - you want at least 100mm with insulation as appropriate. It may sound pedantic, but the air brick location is wrong, and on a personal choice basis, I would have higher dwarf walls.

The insulated slab could be formed by insulating over your existing slab and screeding over. However, you must decide if the existing slab is suitable - many have inadequate hardcore and compaction and many are tilted/out of level.

But also look at your 2 metre dimension. This gives a woeful "room" and all the more so if you have dwarf walls which cut into this dimension.

Furts

Frank99 wrote: »

Thanks for the picture, this is a real eye opener for me,

Which is why my #5 suggested you sort out your design. There is far more to properly building a conservatory than national companies allow for. Indeed, national companies are clueless on all this and only interested in maximising commission.

Now step back and do a reality check ... have any of the national companies given you accurate working drawings, along the lines of that shown by Warwick Hunt but brought up to date with all errors omitted? I cannot answer on your behalf, but my experience tells me it is 99.9% certain you will have nothing from them. Plus this is deliberate because they are clueless and do not care about such things.