Garden Office Roof and Cladding Issues

[Building Time]

Hi everyone,

We’ve recently had a garden office built. Generally, we were very happy with the finish, but it was only finished in August of this year and we’ve already noticed some problems (that I’m pretty sure we shouldn’t be seeing this early, if at all). Firstly, on one side of the structure (the back, which I hadn’t checked for some time) the boards on the roof have taken in some water which has separated them. This was the only side that didn’t have a lip covering them and I wondered if they expected the angle to on the roof to reduce water intake here but I guess they weren’t sealed or some other issue has occurred. Not sure on the properties of the roof but I imagine it has a fibreglass top or something similar.

Secondly the cladding has popped away from the structure in a few places (I’m pretty sure the cladding is Siberian Larch). I don’t know whether this has occurred because water has got in behind, or because of changes in temperature (but if so this should have been accounted for when fixing surely?). Also on this back side the cladding already is discoloured which is fine in itself (I believe they go silver over time anyway) but I wonder if this has been accelerated because of these issues.

I have spoken to the original builders, and despite being a little evasive I’m hoping they will come and fix the problems as soon as possible. I guess my main questions would be what people think the issues might be and the required solutions so that I make sure everything is sorted if and when it is picked up by the builders. Secondly, is there anything I should be doing in the meantime to prevent any further complications and keep upkeep to a minimum?

I’ve added some pictures to help, any help on this would be really appreciated! Thank you so much for your time.

 

[big-all]

when are they going to finish it with felt/rubber or fibreglass as a waterproof roof rather than an unprotected roof ??

 

[JohnD]

it looks like it was not delivered as a shed kit for self-assembly, but constructed by somebody who considered himself to be a carpenter or handyman, is that right?

I see it is clad with vertical T&G, and has no visible gutter, and the cladding boards were fixed when dry, with no allowance for expansion due to weather, and I see no preservative or water repellent stain. Or is the cladding shiplap, which has incorrectly been fixed vertical? Am I right?

If so, I wouldn't trust the original builders to be competent to repair it.

Where did you find them? Have you paid?

I can't see what the roof is made of. Cardboard? Delaminating ply?

Photos of the construction from the inside would be useful.

Are you fit enough to do outdoor DIY?

 

[Notch7]

The roof deck boards are cream crackered and need replacing.
The roof edging detail has not been completed properly.

Hard to tell on the vertical cladding but I would say insufficient expansion gap.

Be aware that the correct detailing for vertical cladding is: vertical battens then counterbattened with horizontal battens.

Its impossible to tell if the claddibg is siberian larch or pine -the grain pattern is very similar. Its easy to tell on an offcut -siberian larch is as heavy as oak.

 

[Building Time]

Thanks for the replies everyone. If I replace the edge boards can you cut away the affected areas and replace or would the entire roof need replacing? It's a 30 square metre space so replacing the entire roof would be a nightmare.

If it's just the edge boards that need replacing after they've been finished can I just do the edging properly so that this won't occur again and if so what's required?

I've just checked and the original contract had the roof down as a GRP roof. The boards that have separated look like some sort of plywood perhaps but not sure as I'm not very knowledgeable in that area.

There's definitely no gutter, and they have been fixed vertically as you say, with what seems like no space (or little space) for expansion. So would these all need replacing now (or can they be reused even?)? They definitely had a preservative applied although I haven't taken note of which one.

I could show you pictures of inside but not sure that would help as it's a plaster finish so it just looks like a decent job at the moment!

It wasn't constructed by a handyman but by a building firm who build houses! This was quite a minor project for them (but a big one for us) so they're certainly not a small outfit, which is why it's such a shame that they've not done this to a required standard. They have unfortunately been paid, and it wasn't a small amount!

 

[John D v2.0]

I've just checked and the original contract had the roof down as a GRP roof. The boards that have separated look like some sort of plywood perhaps but not sure as I'm not very knowledgeable in that area.

Take a photo of the top surface. At the moment it just looks like plywood that has been left outside without protection. I've had an old bit of plywood outside for a few years protecting the compost and it's gone like that on the edges.

There's definitely no gutter, and they have been fixed vertically as you say, with what seems like no space (or little space) for expansion. So would these all need replacing now (or can they be reused even?)? They definitely had a preservative applied although I haven't taken note of which one.

Timber always expands much more across the grain than along it. If it's forced its way off, either it was too dry when fitted (should be getting on for 20% moisture content if it's for outdoor use I would have thought) or it was fitted too tight to each other.

You mention it was a big building firm did it, was it persimmon, I've heard they are doing well! Either that or the big firm got the apprentices to do it as a practice job.

 

[^woody^]

It wasn't constructed by a handyman but by a building firm who build houses

It wasn't Persimmon was it?

It's bad. That roof edge is wrong and will be difficult to remedy now as it's all blown and delaminated.

 

[Building Time]

Yeah, it looks like there was a GRP resin applied to the top layer but the edge has just gone on one side where it wasn't sealed/ protected properly. I just need to figure out what to do next, will i be able to remedy just the edge part of the roof or will it all need replacing? Just wondered if I could cut out the affected part and put a new bit of board in and seal it

 

[Alexnh]

Yeah, it looks like there was a GRP resin applied to the top layer but the edge has just gone on one side where it wasn't sealed/ protected properly. I just need to figure out what to do next, will i be able to remedy just the edge part of the roof or will it all need replacing? Just wondered if I could cut out the affected part and put a new bit of board in and seal it

It looks like you've already got several problems that are caused by very poor design and build. are you saying that the whole roof is just ply painted with resin? Can't see what lasting very long. Why should you be fixing their mistakes? I'd be very surprised if you don't discover more shortly. Post some pictures of the whole thing.