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Foundation question

Apip99

Afternoon all,

I wanted to ask about foundations. Does any body know what depth is it best to dig out for a normal house extension??? Size will be about 20 square meters.

I'm planning the extension for my next project, and will be doing most of the donkey work myself, so may be back an forth here asking questions.

Thanks in advance,

Phil

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Corkey123

I did this recently and was advised by an arachitect to go down a foot deeper than the existing founadations with a view to having the concrete poured to the depth of a foot to meet the existing foundation level. The width of the foundation was twice the width a cavity block or 18" - Is that clear?

At the lowest level I was five foot deep.

It will be interesting to hear other opinions.

Apip99

Thanks for replying,
Have you finished you extension now?

5ft sound deep. I was working on the thought of about a meter. But I guess its better to be safe than sorry. And I just hope that a mini digger can get round the side of my neighbours house. Mine is a no go as I built a lean to running most the length of the house last summer. If no look like I'm going to have a hell of a lot of manual digging to be done.

Out of interest, how much did it cost to get the foundations poured. And who did you use. I see you are in Bray we're in Greystones so looking to use local companies where possible.

Thanks in advance,

Pip

Corkey123

Yep it all finished .. and still standing.

You probably not going to believe this but I dug the foundations myself. I have a side entrance but it was too narrow to get gear in so I pickup the shovel and a month later.

A couple of tips if they are of any use. When you make mistakes doing this kind of stuff it can cost you big time and I made some so here' s a couple of pointers.

As you dig be it manual or by gear remove the soil out the front. You might think you have plenty of room out the back.

Get all your ground work agreed in advance Services etc. as a change half way could cost you dearly.

Lay as much reinforcing steel as you can, don't be shy with it,

Have plenty of mates around when you get your delivery of concrete. If it begins to set you fuc***. Maybe consider an inhibitor in the mix.

Just got the delivery from roadstone cheap enough if I can recall 300 or 400 Euro.

Be careful of the main waste you will have to provide some knid of protection.

Sorry didn't use any local trademen/companies other than for block and cement. The rest was DIY. I'd recommend Heitons though instead of Chadwicks.

Mine was a tale of woe with a builder who let me down badly, so I decided to get my own back and did it myself.

Let me know if you need anything - I'll probably have it lying around.

Apip99

HI there, Thanks for getting back, and for the heads up on problems.

I’ve just take delivery of my Bricky Tool, which came with a great DVD. Start to finish of how to build. Of course the guy (Cork lad invented it) makes it all look dam easy. So looking forward to getting stuck in, although I know I won’t be saying that when I’m getting a dose of trench foot!!! LOL

That doesn’t sound too bad at all about the cost for the foundations, better than I was thinking. What about the fill for the floor cost wise. Expensive?

The only thing I see me needing at the moment is a cement mixer. I missed the one at Alsi for 200 Euro the other week. So just, may see how much to rent for a while.

Thanks again and speak soon.

Corkey123

You can use any old crap as filler. You can get hardcore fairly cheap if include it with sand and cement. But do place some steel over it first. Your looking for approx 6" of concrete and don't forget the damp course.

Last time out in B&Q they had an electric mixer for €280. You can alway sell it when you finished.

rooferPete

Hi,

The rules or guidelines are dig doiwn until you hit sub soil (yellow clay), there is no hard and fast rule about the depth because if your house was built on made up ground you may have to install a raft foundation.

The width should be three times the width of the wall, with the wall built in the centre of the foundation.

.

ifah

just to give you an insight into my experiences - am currently building a 40m2 extension - you won't get an engineer/architect to sign off on the building (cert of compliance) unless you conform to standards and you will definitly have problems if you try to sell without a cert.

Based on that my engineer specified that we had to go down to the same depth as the existing foundations of the house - started digging two weeks ago with a 3 ton digger and 3 ton dumper - after two hours we had to stop as the arm wasn't long enough to reach - had to get a 5 ton digger (luckily I have plenty of space by side of house) and we went down 7 and 1/2 feet to top of foundations of house - we stepped the foundation up 1 1/2 feet about 6 feet from house to save height. Total amount of soil/fill dug out and disposed - 85 tonnes. I had planned/budgeted for 30 tonnes so imagine the surprise ! - To remove each 20 tonne load was € 330 + vat. Also as RooferPete said - foundation must be 3 times the width of the wall - if using 9" cavity - foundation width = 27 ". I'm using 4inch solids with 4 inch cavity so foundation width = 36 ".

Am now ready to pour the floor but it's been hard work getting this far.

Also op - you stated you have already built a lean to all along the side of the house - what is the total square metres of that and the extension as you may need planning permission if you're going to be above a combined 40 m2.

Apip99

Thanks all for you replies.

The lean to is not a problem as its a timber construction and does there for can be taken down with ease. I checked with planning requirements for that and they said it came under the garden shed bracket, and the fact its only 3 1/2 meter sqr, it's not intrusive. to any one, as its to the back of the house. Plus I'm not going to full 40sqr for the extension. I need to leave me with some garden!!!!

There was a mention of engineer/architect to sign off on the building (cert of compliance) by AFAH. What is the story with that side of things. I have no architect working with me on this. My drawings are being down by a colleague who is an Ex-Architect. She now works as our CAD design manager. Would I have to get the building reviewed at stages by some one from the council?

Thanks in advance,

Pip

ifah

You shouldn't need to get someone from the council involved - a certified structural engineer should be able to do this for you. My future brother-in-law is my engineer so I can't pass on his details but i'm sure there have been engineers recommended previously on the site. The Cert of Compliance is just that - a certificate that states that the building has been carried out competently, is of an acceptable standard and does not contravene any planning regulations - but the engineer will want to see the building at the various stages to ensure all is kosher as it progresses. This cert will then be available should anyone (eg nosy neighbour) object and the council got involved.

One other point to note and it's a very important one in this era of waste management - part of the compliance is that all building debris has been disposed of in a safe manner in a registered land fill - you may be required to show receipts showing where your debris has gone depending on the area you're in (again if the council get involved in dispute).

darkbeatz

so if somebody builds a shed in their back garden under the 40sq m restriction will they still need to have a certified structural engineer sign off on it?

ifah

afaik different rules apply to non-habitable (ie shed) and habitable (extension) buildings. there are documents outlining all of these building regulations on some of the local authority websites but I don't have the url to hand at the minute. I do know there is a restriction on a shed/garage of 25m2 before you need planning dependent on it's location and garden size.

darkbeatz

cool thanks for the reply

Corkey123

Apip99

I have just completed a construction, similar to what you are starting. We are/were dealing with the same authority. I wasn't asked at any stage for a certificate of compliance. I was asked for a commence notice and fee, which was refunded on the council inspector viewing the plans and the finished construction.

A friend of mine who is a local architect never mentioned a certificate of compliance and no one has asked for one to date. I have no doubt the contribution to date are all in your best interests, however some are dealing with different local authorities. I suggest you confirm all with your local planner

ifah

Excerpt from Building Control section of Cork Co Co. below :

The same section details are also available on Cavan Co Co, Monaghan, Kerry, Donegal, ... got tired of searching on google at this point - all of these make reference to the Building Control Act which is not area specific - so no offence MartinCorcoran but I'd check with your architect - remember you only need a cert of compliance if either the council get involved in any disputes or if you go to sell your house.

I am in the lucky position of having three family members who work in planning so my knowledge comes mainly from them - one of them told me of a famous case a few years ago whereby a neighbour took exception to an extension that person X built in North Dublin - the council investigated and his extension was deemed to be 40.12 m2 - after a long legal battle person X lost his case - had to pay all costs and then had to apply for Retention which he eventually got after shelling out thousands in the courts.

1. What are building regulations?

Building regulations are a set of legal requirements for the design and construction of new buildings, extensions and material alterations to, and certain changes in the use of, existing buildings. Building regulations provide for the health, safety and welfare of people, conservation of fuel and energy and access for people with disabilities.

The Consolidated Regulations came into force on 1 July, 1998, and replace the Building Regulations of 1991 , as amended. The amended Part M came into force on 1 January, 2001. The amended Part L, relating to new dwellings, came into force on 1 January 2003; and relating to the replacement of external doors, windows and roof lights, on 1 July 2003.

2. How are regulations framed?

The regulations comprise a set of legal requirements, expressed in simple, functional statements.
They address the following:

Structure
Fire safety
Site preparation and resistance to moisture
Materials workmanship
Sound
Ventilation
Hygiene
Drainage and waste water disposal
Heat-producing appliances
Stairways, ladders, ramps and guards
Conservation of fuel and energy
Access for people with disabilities
Technical guidance on compliance with these requirements is set out in twelve separate Technical Guidance Documents, which deal with each of the above areas.

3. How do regulations affect me?

If you are having work carried out, it must comply with the regulations. Regulations do not apply to works consisting of repairs or renewal.

4. What if I fail to comply?

The primary responsibility for compliance rests with designers, builders and building owners. Building control authorities have power to inspect design documents and buildings, as well as powers of enforcement and prosecution where breaches of the regulations occur.

There are heavy penalties, including fines and imprisonment, for breaches of the regulations. In addition, when it comes to selling your property, you may have difficulties if you cannot satisfy the purchaser's solicitor that the requirements of the regulations have been met.

Corkey123

Thanks for info ifah,

rooferPete

Hi Martin,

The real issue with Certificates of Compliance (opinions of compliance) come to light should you decide to sell your house, they form a similar role in your property folio as the Planning Permission or certificate of exemption.

.

Steve

rooferPete wrote:

The real issue with Certificates of Compliance (opinions of compliance) come to light should you decide to sell your house, they form a similar role in your property folio as the Planning Permission or certificate of exemption.

This only applies to the cert that says you complied "substantially" with planning permission (if it was needed in the first place). Completion certs for work that was exempt or not needed - e.g. loft conversions - will not affect a sale. The exception to this is if the buyers bank looks for a cert and there isn't one - or - the banks surveyor reports anything dodgy - then they'll think twice about issuing a mortgage.

It's like buying a car without an NCT cert - not illegal but you'd think twice!

There's loads of houses bought and sold with dodgy uncertified extensions / loft conversions etc.. people in general haven't a clue what they're buying. People buy houses after a 1/2 hour viewing because they liked the area / decor / garden / smell of fresh baked bread in the kitchen.... there's too few who'll lift the carpet / sight the roofline / check the plumbing etc before parting with 25 years of cash!

Sorry - just had to say that 'cos it nearly happened to me! My surveyor spotted a slight sag in the roofline of a house I nearly bought - on further investigation, the cowboys that did the loft conversion 6 months previous didn't use the correct joisting and the whole roof started to sag!

fdevine

Unless you have retained an architect or engineer to supervise the works at the various stages, you will never get a legit full certificate of compliance.

Im not saying this is a problem, as you can get a 'Certificate of Substantial Compliance'. This will be sufficient for the purposes of selling your house, if the time comes.

Do try to comply with as many of the Building Regulations as possible, in particular with regard to insulation. While planning permission is not required for extensions up to 40 sq.m., all construction must comply with the current building regulations.

They dont make for light or easy reading, but have guides regarding foundations, sizes of opes and panels between opes and the like. Should be able to view a copy in your local library.

Steve

Current Building regs can be downloaded here.

http://www.environ.ie/

click on "building standards" then "technical guidance docs"

I agree - heavy reading alright...

rooferPete

Hi stevec,

Basically all certificates issued by an Architect or Engineer are limited to the words "Opinion" or "Substantial Compliance", the only way they could issue a Certificate that is "Iron Clad" is if they stay on site, observe and record each detail which is not really an option.

While people today may buy property with questionable title they are either willing to gamble or they have terrible legal advisors who are not even attempting to do their job.

The days will return when the buyer will have more choice in the market or at the least will have other options and will not need to gamble, I believe that is the day all people who are carrying out what are costly improvements may be sorry they did not seek professional advice before spending their hard earned money.

The Banks and Builing Societies will also revert to more cautious lending where they will demand the risk element is reduced by having full and clear title before releasing the funds.

Caveat Emptor

Corkey123

Lets get back to Apip99's intended construction and the issue thereof. On foot of ifah's contribution, which was very helpful, I contacted my architect regarding the certificate of compliance, as I don't have one and I needed to know if and when I should obtain. This is just to establish what Apip99 needs to know if he is advancing his project.

Firstly - The certificate is not related to the planning process and Apip99 can advance without one.

Secondly - The local authority do not in his case require that he has one to begin or finish his project.

Thirdly - It is usually required in two cases,
(i) where finance is being drawn down from a loan institution and/or
(ii) when you are selling you house having made constructional improvements that require planning prermission, as it is deemed part of your deeds documentation.

The issue related to the later is that the certificate relates only to the work carried out under the original plannning persmission and not work that was carried subsequentlyout over the next ten years. For this reason the Compliance cert may have to be refreshed on the request of the buyer of the property.

Going back to Apip99 -
Does he need a cert one to begin his development? No he doesn't.
Should he get a cert after the development - Its up to him though I'd say yes, but it is not obligatory.

ifah's suggestion that you won't get architect to sign off on the project unless it is compliant is probably correct, therefore (no disrespect to your friend) get a qualified architect to sign off on the plans at the least.

Now off you go Apip99 and get diggin'

Apip99

Afternoon all.

Well what can I say. You've all been great with you info.

In the mean time I too had been speaking with friends in the know, and they have al said pretty much the same. (Oh, SteveC , Love the NCT comparission)

I'll be in touch with an engineer as I go along. Better to be safe then sorry. The I'll work towards get the certs I need. Not that I'll be selling in the near future after building the dam thing!!!!

Thanks again guys, a wealth of information has been made available. Hopefully with in a few months I'll b able to share my experience with those daft enough to be undertaking such a job!!

Steve

RooferPete / MartinCorcoran,
I totally agree with your posts - it only becomes an issue when the banks get involved, I'm not sure but I think insurance companies get concerned as well if theres no cert and will load the building cover.

Apip99,
I spoke to a mate who recently built a side extension - there was planning permission required and the guy from the planning office made several visits as work was in progress. The work involved re-routing some soil pipes and drainage which was done at the same time as the foundations. A week later, the planning guy insisted on them being dug up for inspection! This shouldn't be an issue for you though if there's no planning involved. Be sure the engineer tells you about anything he needs to see (foundations / lintels / whatever) as part of his certification before it gets covered.

muffler

darkbeatz wrote:

so if somebody builds a shed in their back garden under the 40sq m restriction will they still need to have a certified structural engineer sign off on it?

In a word - NO.
I think most of the requirements have been covered by the other posts but the position is that if your extension/garage/shed is classed as exempted development then you do not have to submit a commencement notice to the Building Control Dept. nor do you need anyone to supervise the works.

However your extension/garage/shed still must be constructed in accordance with the Building Regulations. If you have any sort of mortgage taken out to cover the works then you will need to have an architect/engineer retained to supervise the works and issue you with a cert. compliance upon completion.

If you are funding the works with your own cash or with a personal loan from the bank then it is entirely up to yourself as to whether you have an architect/engineer present. But as already pointed out it would be wiser to have someone oversee the works and issue the relevent paperwork should you ever wish to sell or indeed even remortgage the property. Leaving that aside it, unless you are in the construction business yourself it is highly recommended to have someone there just to keep any eye out for shoddy work etc.

muffler

Apip99 wrote:

Hopefully with in a few months I'll b able to share my experience with those daft enough to be undertaking such a job!!

Nah. An invite to the room warming party would be fine

karltimber

So - my question on the subject of eng would be --

I am doing a self build ext that I got planning for -45msq
A friend did the plans for us so no architect was involved.
Am using different trades people along the way.

Do I need to hire an Eng to oversee the project and sign off a cert at the end and where's the best place to source one --Navan area.

thx

muffler

karltimber wrote:

So - my question on the subject of eng would be --

I am doing a self build ext that I got planning for -45msq
A friend did the plans for us so no architect was involved.
Am using different trades people along the way.

Do I need to hire an Eng to oversee the project and sign off a cert at the end and where's the best place to source one --Navan area.

thx

As stated in my post avove, if you are in a mortgage situation you will have to engage someone otherwise its optional but read the post above and in any event dont forget to submit your commencement notice

Apip99

muffler wrote:

Nah. An invite to the room warming party would be fine

Invites will be issued to all those who have help and/or hindered upon completion.

Here's my plans from my Architect. Are you all sure that I will not need planning permission?? http://www.alphabet-soup.net/goose/oldwomancolor.jpg

On a serious note, all looks great on plans and now wanting to crack on. Just get Paddies day, The England Ireland rugby, and then the hangover from hell out the way, and and the weekend will be taken up building.

muffler

Apip99 wrote:

Here's my plans from my Architect. Are you all sure that I will not need planning permission?? http://www.alphabet-soup.net/goose/oldwomancolor.jpg
.