Sunken/rotting conservatory floor - how much is this going to cost? 😫

[MindatWork]

Hi all - we have a floor to ceiling glass conservatory across the back of our house, built by previous owners (think it’s around 13/14 years old). A while ago we noticed that the tiled floor in one corner looked like it has ‘sagged’ a bit, and that the join in the fascia panels on the corresponding outside corner outside at floor level had blown, evidently letting water in underneath. The conservatory juts out into the garden so it goes straight onto earth/grass at this point, although I assume there’s a concrete base underneath.

We’ve got someone coming to look at it in a couple of week’s time but we had an electrician in today (to isolate a floor plug socket in the damp corner), and when he took it out he said the floor joists were rotting away and it was really damp underneath.

I’m really worried we’re going to have to rip the whole floor up and redo it. If we were planning on staying we’d knock it down and do a single storey extension but we’re planning to move this year, so are trying to get the house ready to go on the market.

Obviously it need to be made safe and watertight before we sell, but I really don’t want to have to spend £1000s when any eventual buyer may tear it down anyway.

Has anyone been in this situation before? I know a lot depends on how bad the rot is and what sort of damp proofing is required, but any advice would be much appreciated.

Safe to say we won’t be buying another house with a conservatory....

I actually think it will need to come down. Something similar happened to a friend and it needed completely replacing. Personally I would explore the cost of ripping it down and having extra garden space.

It adds a lot of space to the footprint of the house - it currently serves as playroom/dining room as the only other downstairs space is kitchen with small island and living room (stairs are open and you have to walk through it to get to kitchen so limited with where we can put furniture etc).

What a nightmare! Even pulling it down and landscaping garden will be a considerable cost. Seriously considering doing a temporary fix and part-exing to a developer for a new build at the moment (joking!)

Is it a suspended wooden floor on a concrete base or on bare earth and brick sleeper walls? Are there air bricks for ventilation in the sub floor?
Is the conservatory frame on blocks/bricks/concrete footings?
If the frame is on solid footings then it ‘should’ be possible to take up the floor and either put damp proof membrane + insulation down and fill with concrete - £300 ish . Or rebuild a properly ventilated joist and osb floor, probably a slightly cheaper option assuming your have the correct tools for the woodwork.

Thanks for that info @GenderApostate19 - I’m fairly sure it’s a wooden baseboard concrete - there are upvc fascia boards around the base of the conservatory (the floor is raised up from ground level by about 2 feet). I can’t see any vents anywhere for ventilation

Wooden base on concrete that should say

you will have to work out if the conservarory way built first and then the fkloor; or if the conservatory is standing on the floor. More photos inside and out will help.

With luck, the conservatory will have been built on a concrete slab with a dpm, but I have a feeling, not. That would make it simple to pull up the old floor and lay a replacement.

Lack of ventilation to a wooden floor indicates ignorance and shoddy work.

If it’s damaged your house insurance won’t cover for that but may cover the cost of rectifying the damaged floor etc

yu might find, under the floor, an old drainage gulley, or rainwater pipe, that has been left and may be a source of water.

Take up the floor covering and prise out some of the floor then we can see more. Doesn’t sound good :(
Have you thought about doing the extension before selling?

@Loofah01 we have a 2 year old and are not confident diy-ers at all so not really keen to go prising up the floor! Will come back with an update when the guy has been round tho 👍🏻

It’s a massive conservatory and it’s only one corner that has sunk - the floor everywhere else is pretty solid, it think (am hoping!) it’s just this one corner.

We’ve discussed the option to do the extension but we just don’t have the headspace / time / vision to sort (lots of other things going on with work and family). Would also rather sell it to someone who knows what they’re going to do with it rather than do something that just works for us iyswim? There are lots of other things about the house that don’t really work for us otherwise we’d consider staying and doing the work.

Apologies, I’m rambling now! Appreciate everyone’s input

I would get a joiner / handyman who will take up that corner and see if you can do a piecemeal replacement. Until you see what's underneath it's impossible to guess a solution. They may be able to cut out the rotten bit and just replace that if the rest is solid. Unfortunately I don't think you can just hope it will go away you are going to have to open it up and have a proper look.
I would try to improve ventilation under the floor if it's a suspended timber floor as if it currently has none that will definitely be exacerbating the problem whatever it is. We put in additional air bricks as ours were blocked by the previous owners when they built the conservatory but made sure we had mesh covers to try to cut down on mice visitors. It was a simple job and we had to go through brick of yours doesn't have a brick base then it should be even simpler.

@wonkylegs thank you yes that’s more along the lines we were hoping, to get someone in who will be able to repair as much as is needed to make it safe/stable without having to knock it down!

Obv we will have to have the floor up, in my last post I just meant we don’t want to rip it up ourselves now when we can’t get anyone in to look at it properly for a couple of weeks.

We would never try and hide it or sell the house without fixing it properly so I guess it costs as much as it costs

Thanks to everyone who commented before - the guy has come to look at it so thought I’d update.

Basically the conservatory was build on a timber frame on top of proper brick footings, then a plywood floor on top - all standard. There was a leaky gutter on the corner where the damp has got in; we’d had the guttering replaced but apparently a design flaw in this type of conservatory means the seals were still letting water inside 😑.

The ply underneath the tiles is completely damp but he seemed confident it’s a just case of taking the floor up in that corner, replacing the ply and sealing it back up again. Best case scenario, £600 - the issue is they won’t know how far the rot goes until they have the floor up, and if the supporting beams are rotten as well then we’re in trouble.

On another note, he said the previous owners should NEVER have put tiles down in the first place as you always get movement with a timber frame; it should have been laminate or lino. We’re assuming the previous owner did the flooring himself as we’ve discovered various other things that have been bodged around the house. We’re seriously considering taking the whole floor up and redoing it with laminate as almost every tile is cracked anyway, and the tiles will be extremely expensive to replace. Will be nicer for us while we’re still here and hopefully easier to sell.

Thanks for all your comments, we have the worked booked in for 3 weeks time so please keep your fingers crossed for solid support beams!

Are you going to ventilate the void for the future?

@PigletJohnyea sorry forgot to mention they are going to put ventilation in as well.