Hi
Firstly can I say I commisserate with you over this unfortunate situation.
There must be hundreds if not thousands of people in a similar predicament.
Hopefully the responses to this thread may shed some light on how you might progress.
First off and ignoring your post totally for a minute, don't be afraid to talk to your local authority.
County Councils are staffed by public servants many of whom are engineers and they have huge local knowledge.
It may be that thay know of an old report never implemented or new measures not yet publishes that could help you.
All elected representtives in local authorities affected by the flooding are coming under huge pressure to deal with this.
Back to your questions, and I should note that this is preliminary advice in the most general sense, remote from the action.
You absolutely need to take competent professional advice and not rely on local builders and/or demolition experts to do this.
Most demolitions costings will be for blockwork demolition and massed concrete may be significantly more difficult to take down.
There are several types of massed concrete and inter alia, unreinforced 150mm clinker walls will be easier to remove than fully 250mm vibrated 65N reinforced concrete.
The problem is without an engineers assessment, you won't know which is which. If special equipment or special demolition rechniques are needed, this may affect the price.
The issue of raising the house should be seen as a possible recommendation arising from the Engineer's Flood Report. This may also give it the weight it deserves because any proposal to the Council may be affected by the nearby SAAC. Apart from architectural treatment, this could also be because of your increased elevation, prominence in what may a flat landscape and possible overlooking. The engineers report should deal with issues in relation to ground conditions, both seasonal and during return flooding and the raising of the ground and the suitability of drainage arrangements should follow from this. Competent professionals like architects and architectural technicians defer to engineers in matters like this, because the solution to your plight might require flood defense works affecting an entire region.
Raising the ground levels takes you into the realm of "made ground" or "filled ground" and this usually required building on piles or columns with a suspended ground floor if the total fill is more than 1200mm deep. Piled fonudations may be required for the ground here anyway and may prevent the multi-storey respose suggested below. Alternatively, a reinforced raft foundation may be workable, but this may not be compliant in Part A and your engineer will advise.
Your suggested rise of circa 900mm may get you above the current flood level, but that's why the engineer's flood report is so important. You may need to rise up a storey height or more. To do this by raising the site might incur huge expense. Building the lower floor in reinforced concrete but keeping it mainly as storage and access while living on two floors above this may be the most appropriate solution. Buildings of 3 stories may not be the norm in the nearby SAAC, but the typology exists here and in England of the Great House and it could be scaled down with the top level as a dormer or done in a modern idiom entirely. This would allow your site ot be flooded at some future time but your interiors, and valuables to be kept above flood level.
This might be dealt with in part by the sorting out of the current confusion outlined in the recent Prime Time programme dealing with who controls the Shannon Water levels.
If persons or bodies with responsibility OPW, Inland Waterways, Local Councils are found culpable for not acting in a competent, responsible or timely manner during the recent flooding, there may be scope for a legal action on your part which, while not necessarily going to make you wealthy, may at least clear the path to allowing you to, for example, raise ground levels and get permission for a non-traditional house in this location. So, yes, you could be refused permission for something like this but it possible that cash-starved Councils will be willing to listen to design-based solutions as opposed to suffering at the hands of the legal profession taking action on behalf of perhaps thousands of litigants.
You'll see from the above that I have pointed you squarely in the direction of taking professional advice from an engineer. You will also need to appoint an architect IMO to develop the house design in consultation with your engineer and ensure compliance with the regulations. For example, if you are considering raising the site as opposed to building a three storey, you will still need specialist foundations and a place from which a disabled person can alight to access the house, assuming you have the space to do all this. Also raising the house may make you more exposed to prevailing storm winds and careful detailing, wind bracing, roof fixings and materials choice will be needed. You may need other building professionals and a solicitor.
I know this isn't the one-stop-shop you may have been hoping for, but I hope it may be of some help and might point you in the right direction.
ONQ.
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