Flat roof parapet wall repair - is this realistic?

[hamburgers]

Hello, 

 

I am buying a house that I know has a flat roof parapet wall (8.5m x 4.5m) that is in poor condition. The rest of the house is pretty good. I need to make sure I factor in the cost of a parapet wall repair this year. I got a roofing contractor to take a look and he has come up with the below. Is what he is suggesting the standard practice when repairing parapet walls or is he recommending I implement the Rolls Royce solution (which will mean I will be eating baked buns for lunch for the rest of the year):

 

Zinc Capping System to top of the Front Parapet Wall

Clean off and prepare existing brick and wall surfaces ready to receive new zinc capping system.

Supply and fit exterior ply-decking this to include all associated furring timbers fixed securely into position by means of screws and raw plugs ready to revive new zinc capping system.

Supply and lay megaspaan underzinc felt lay loose.

Supply and fit 14 gauge zinc sheeting dressed and formed into capping’s single welted, these to be fixed securely with zinc clips, this to include all necessary seaming, welting and solder burning as required including the forming of drips.

Supply and fix new zinc cover flashings fixed securely to the existing decking with galvanised nails, dressed and formed including the welting onto covering with an outside lip ready to receive welted sheeting on zinc sheeting.

Total Cost for Labour and Materials…….>£1,275.00 +vat

 

Inner Parapet Wall Render

Hack off existing sand and cement render to the front inner parapet wall bag up and clear.

Brush down and Unibond brickwork ready to receive new materials.

Supply and fix metal renderstop bead and stop beads these to be fixed securely on to the abutment walls by means of screws and raw plugs.

Supply and lay new sand and cement render to the complete parapet wall this to have a mixture of a 3;1 sand and cement mortar finished with a fine washed sand with an added Waterproofer and Unibond mix, finished coat is to be by means of a trowel finish and leaving all works clean and tidy on completion and in a watertight condition.

Total Cost for Labour and Materials…..£5,000.00 +vat

 

 

Thank you so much for your advice!

 

Edited August 13, 2021 by hamburgers

[markc]

Good morning and welcome,

the zinc work looks very reasonable.

the render initially looks high but you do not say how high the parapet Wall is? or the access available? Vehicular access etc. 
overall I don’t think it’s bad at all, especially after seeing some prices for poor work done recently.

[tonyshouse]

I hate parapet walls! Can you knock it down to below roof level? They leak heat, leak and leach water in, gather condensation by pumping it from the house, cost too much to repair - repeatedly 

[hamburgers]

Hello,

 

Thank you for the warm welcome

 

The roofer would have to put up scaffold (he quoted £595 + VAT) to access the roof.

 

I can only knock down one side of the wall (lower rear end) - the other sides are shared and the front side joins with the neighbour's parapet wall, as it is a terraced house.

 

The wall itself is about 0.75m high on the rear and front, whilst the shared sides are about 1.5m high. I think I will ask for the rear parapet wall to be removed, as I would like to deck out the roof in the future - the rear side would provide access to the roof from the garden.

 

Below is an image of the rear parapet wall, with a view of the shared side walls. Pretty shocking!

 

Thank you!

 

 

[Ferdinand]

Does i require planning to remove a parapet wall?

 

I don't know.

 

Not that it looks like the neighbours opposite will mind.

[hamburgers]

Hi Ferdinand, I would remove the rear parapet wall seen in the photo above that is made up of a mixture of breeze blocks and red brick, which I believe the current owner put up - that section does not need planning permission to remove. I would have this section of the wall removed to the point where you can see the original white ledge.

 

Thanks!

[markc]

Omg! The masonry is in a bad state, definitely needs work to make it waterproof. 
looking at the pics the quote is more than reasonable.

as above, parapet walls are always more trouble than they are worth. 

[nod]

Rendering with sand and cement will not be a permanent cure 

First you will need to stabiles the masonry

This can be done by drilling and fixing a s steel mesh You then need two coats of sika bagged render Expensive but totally watertight and permanent 

 

Ive used this on the bottom of lift shafts whilst pumping water out 

 

Any render beads will need to be S steel 

[hamburgers]

8 minutes ago, nod said:

This can be done by drilling and fixing a s steel mesh You then need two coats of sika bagged render Expensive but totally watertight and permanent 

 

 

Hi @nod,

 

Thanks for the advice. Will this add a significant amount of cost on top of what I was quoted for the work? I have no idea about these things.

 

Thank you!

 

 

Edited August 13, 2021 by hamburgers

[Ferdinand]

Indeed. Not paying attention to parapet walls can have consequences. 

 

Good that you are taking the time to address it.

 

https://www.theguardian.com/money/2012/jun/02/deborah-orr-roof-silent-disaster

[nod]

48 minutes ago, hamburgers said:

 

Hi @nod,

 

Thanks for the advice. Will this add a significant amount of cost on top of what I was quoted for the work? I have no idea about these things.

 

Thank you!

 

 

The render price that he is quoting Is 2 days work for two men with less than £200 in materials and certainly won’t be a long term cure 

 

So pretty high

 

I would at the very least stabilize the walls before doing anything else 

and perhaps get a quote off a plastering contractor for the render 

 

 

[hamburgers]

51 minutes ago, nod said:

The render price that he is quoting Is 2 days work for two men with less than £200 in materials and certainly won’t be a long term cure 

 

So pretty high

 

I would at the very least stabilize the walls before doing anything else 

and perhaps get a quote off a plastering contractor for the render 

 

 

 

Thank you @nod for your insight. 

 

So if I understand correctly in layman's terms:

1) Stabilise masonry with steel mesh and cover with Sika render

2) Zinc cap parapet walls

3) Plaster the reinforced and waterproofed parapet walls.

 

Is this correct? If so, do you think this can be done for £10k?

[nod]

2 hours ago, hamburgers said:

 

Thank you @nod for your insight. 

 

So if I understand correctly in layman's terms:

1) Stabilise masonry with steel mesh and cover with Sika render

2) Zinc cap parapet walls

3) Plaster the reinforced and waterproofed parapet walls.

 

Is this correct? If so, do you think this can be done for £10k?

Correct 

[Dave Jones]

good opportunity!

 

warm roof.

 

alutrix + edpm

[Makeitstop]

£10K...wow.

 

I've had a few 3 bed semi's re-rendered with simple s&c and dashed with 6mm clean limestone for under £5k (I guess it depends where in UK you are). As Nod said, it's a few days work on that job you have there and materials cost is virtually nothing using traditional sand and cement.

 

To me, your price sounds expensive. Also, it may be worth asking for other quotes advice to gauge what everyone suggests as solution. As you've found out here, there are a number of approaches to resolving it, with some being better than others.

 

Doing this kind of thing once only is definitely preferable.

 

 

Edited August 13, 2021 by Makeitstop

[Dave Jones]

its not a days job so lets put that aside.

 

To  sort it out properly and permantly, ie 15 years, will take a weeks work from a skilled team. anything less than £5k and you wont be getting that.

[Makeitstop]

How many in the team?

[Makeitstop]

Have to admit though, that is some absolutely hideous masonry

[hamburgers]

Thank you for replies. It's given me food for thought. I may be out of my depth on this so I'm reconsidering the purchase of this property, which is a shame because the rest of it is great. I think that anyone in the trade will see me as a complete novice and so will try to overcharge. 

[Mr Punter]

Although it is not pretty, is there anything to suggest that the current setup has failed?  Also, how did you get access for the photo?  If it is easy to access you and currently watertight you could just get the wall meshed and rendered and order some aluminium copings that you could install yourself.

[Makeitstop]

1 hour ago, hamburgers said:

Thank you for replies. It's given me food for thought. I may be out of my depth on this so I'm reconsidering the purchase of this property, which is a shame because the rest of it is great. I think that anyone in the trade will see me as a complete novice and so will try to overcharge. 

 

If the place ticks many boxes for you and you generally like it, then I'd not be deterred by a parapet issue, if it was the only glaring problem. 

 

Can't you get hold of a decent builder and get them to come along for another viewing.?...May be worth the effort.