Stripping Cement Render... or not...

[dans]

I'm currently renovating my 400 year old timber framed Norfolk farm house. It his being completely gutted inside and a new roof going on next week. The front Ground floor is solid Brick walls (and an interesting huge Mullion Window!), which probably replaced the timber 150+ years ago. One gable end is completely solid brik. This leave the front 1st floor, south facing gable end and all of the rear of the house completely timber frame.

Repairs have already been made on some of the timber noticeable from the inside of the house. Overall, considering the age, most of the beams are in excellent condition. A lot of the exterior beams are visible from the inside of the house, but only the face of them, as we do not want to remove the wattle/daub and lime plaster infills. Obviously, they could potentially LOOK great but only be 2cm thick!!

The outside of the house is a mix of lime render and (mostly) cement render. A lot of the lime render has been patched up with cement render. It LOOKS ok, but does sound hollow in places when tapped. Some of the render does move when knocked, like it's no longer making contact with the walls. There are a couple of small cracks which could be easily repaired, but otherwise all is very even.

Now; the right thing of course would be to pull off the cement render and replace with Lime render. I am concerned however, what I'm going to find underneath the cement render and of course how much support the cement render is now providing some potentially rotten beams. Am I creating problems when I could just leave as it is??

Penners has seen the house...

The House is not listed.

Any opinions would be appreciated...

Thanks,
Dan

 

[LadyArowana]

The outside of the house is a mix of lime render and (mostly) cement render. A lot of the lime render has been patched up with cement render. It LOOKS ok, but does sound hollow in places when tapped. Some of the render does move when knocked, like it's no longer making contact with the walls. There are a couple of small cracks which could be easily repaired, but otherwise all is very even.

Now; the right thing of course would be to pull off the cement render and replace with Lime render. I am concerned however, what I'm going to find underneath the cement render and of course how much support the cement render is now providing some potentially rotten beams. Am I creating problems when I could just leave as it is??

Penners has seen the house...

The House is not listed.

If there is a problem underneath it's better to find it and do something about it now. Hoping there isn't when you sort of know there might be will only be a source of worry . Ignorance is only bliss when it really is ignorance.

 

[MatthewC]

Now; the right thing of course would be to pull off the cement render and replace with Lime render. I am concerned however, what I'm going to find underneath the cement render and of course how much support the cement render is now providing some potentially rotten beams. Am I creating problems when I could just leave as it is??

You are certainly not creating a problem if you remove cement to reveal rotten beams underneath, just uncovering a problem before it gets even worse! If the cement is supporting the beams then it's going to give somewhen, and it's better that you control the time of that.

My vote (on my limited experience) would be to take the cement off: if there is no issue with the beams then you re-render with lime, and if there is an issue then you really should sort it now (if you can afford it...). You surely won't want to do that sort of work in a couple of years time when it suddenly becomes desperately needed. If you don't do it, and have damp & rot issues in the future, you'll be wishing you had taken the opportunity now.

 

[dans]

Thanks for your replies.

It's going to be our family home for years to come, so I think it probably is the right thing to do. The last thing I want to do is waste money making the interior nice, only to have to pull-back the walls at a later date to make repairs on the structure...

The cement render really is in good condition though, so part of me feels it may be a waste of time.... and money!

Dan

 

[chapel]

Hi Dan,
400 year old timber framed house here too, which we are slowly rennovating.
Unless you're suffering from damp, or there is any proof there is a problem in relation to the support of timbers, I would avoid a complete strip of the render. I just don't see the need and you are making unneccesary work for yourself.
You can always continue to patch if needed - where there are large cracks, blown bits.
Paul

 

[tobydog]

400 year old timber framed house here too. You could always consider having the lower timbers (particularly the sole plate) microbored. You or an engineer could do this through the cement render so it's very low impact. Saves you stripping everything off when it might not be necessary.

 

[dans]

Thanks you again everyone!

What exactly is Microbored?

Dan

 

[tobydog]

Think of it as keyhole surgery. I don't know the science behind it but the attached link should help.

http://www.premier-heritage.co.uk/expertise/non-destructive-timber-investigation/

 

[Carol]

A topical topic here as we start stripping off our cement render next week after ten years of procrastination! It is now beyond patching and hopefully removing the concrete will be beneficial. It has been hollow for ages but began de-laminating badly at the corners last winter and the time has come to do the job. New render will be lime of course, but am most worried about what lies beneath. Maybe parts of timber frame or the original infill will be identifiable, I just hope nothing falls down/out in the process.

 

[Keithj]

Another 400 year old (listed) house. Concrete render had been used, and as a result the sole plates had almost disappeared. The horror story can be seen here.

Have an expert investigate it. If all is well, you'll be happy and reassured. If it's not, you want to know anyway.

 

[Zebra]

Me too, me too!! 300-400 year old brick ground floor, timber first floor house with cement render. Could you perhaps poke a couple of holes in the cement render and have a look at the beams, if you can't get at them from inside? I'm no expert I would add and I might be wrong! But if you can patch the cement render back in if it looks ok then there's not a lot to lose, and it might save you from going the whole hog all at once.
Unlike you I can get at my beams from inside to repair them, and the cement render doesn't seem to have caused any damage to the timber, which is only the first floor. On the brick ground floor it was definately trapping damp. However, I've now had to patch it back in so much around the junctions with chimney, side roof, eaves etc, that it's a mess, and the plan is to replace it all in the summer. But I will be applying sheathing boards to the interior first to support the frame and prevent it twisting before I take the render off, because I don't know how much structural support the cement render is giving the frame, and would be very nervous of taking everything off all at once.
I know that was the case on my side extension which I had to demolish recently - the cement render was what was holding the wall up, and not the timber frame - because the whole sole plate was moving, and I managed to extract the timber frame piece by piece and leave the wall standing! (Not with any roof on though..).

 

[Carol]

Relieved and surprised to see underneath our removed render when I got in tonight, no sign of the timber frame at all but strong sturdy stonework. Now wondering if it is too late to ask for re-pointing not new render. Will look properly tomorrow morning in daylight! I was fully expecting a mish-mash of timber framing, brick infill and rubble stone with lots of rot! Am trying not to think about what might be supporting the ends of the beams. And the old render seems to be all cement too.

 

[Zebra]

Carol, sounds like what you've uncovered is better than you expected, and yet it's left you with a stressful decision to make, whereas the worst case scenario would have left you with only one course of action! Still, hopefully it's nice to know things look sturdier than you expected.

 

[dans]

Thanks again to all...

As always, these dilemmas seem to resolve themselves! In this case a large amount of render has simply fallen off when my builders pulled down a lean to extension! Decision made, it seems!!

All the timber looks good underneath, so we'll just remove anything that looks 'blown; and patch with lime render...

It's funny how you worry about a decision to be made with these old buildings, though eventually the buildings seem to make the decision for you!

 

[MatthewC]

The outside of the house is a mix of lime render and (mostly) cement render. A lot of the lime render has been patched up with cement render. It LOOKS ok, but does sound hollow in places when tapped. Some of the render does move when knocked, like it's no longer making contact with the walls. There are a couple of small cracks which could be easily repaired, but otherwise all is very even.

In which of the above categories was the render which fell off? If it was bad then the fall was to be expected but if it was thought to be good then that's a problem!

 

[dans]

The cement Render came off. We're now checking the rest of the building for blown patches. If extensive, then the whole lot will be re done. If local, then we'll patch it...

 

[Carol]

Ours is all off too now and sadly I have decided that the render will have to go back, although it will be lime now. The stone was lovely but daylight revealed far more brick infill and distinctly poor patches of rubble. Part of the first coat of render was done on Friday. hope this morning's frost won't ruin it!

 

[JohnB]

I did my first bit of serious render removal today. On the left is the end of a block internal wall, and on the right, the nicely botched bricks where the window opening has been changed! There will be more of this :roll:. Fortunately, the plan is to render in lime, and I hope ultimately to externally insulate.

 

[MatthewC]

John

Good job! (How are the knuckles?)

I'm not sure how much spoil there is on the ground, but the ground level does seem to be worryingly close to the floor level, judging by the door cill. Are you going to sort that as well?

 

[JohnB]

John

Good job! (How are the knuckles?)

I'm not sure how much spoil there is on the ground, but the ground level does seem to be worryingly close to the floor level, judging by the door cill. Are you going to sort that as well?

I have plenty of tea/internet/lazing around breaks!

Ground level is almost exactly floor level. It's a concrete path touching the wall, and is on my to-do list! I'm actually working on the room on the other side of the wall, and felt like a change from removing 2 inches of cement indoors, and uncovering and digging out a long lost fireplace. The wall is damp, so I hope stripping both sides will help it to dry out quicker.