I had my first fit of National stables 9 years ago , I was happy with them and therefore returned to them so that my yard matches just over a year ago - we had a normal 12x12 stable that is absolutely fine but we also had a 16x16 box which very quickly went VERY mouldy due to lack of ventilation - when I first contacted them they tried everything out the blame back on me ( bedding etc ) but the stable was treated exactly as the others are - the mould in the roof and walls get very quickly and I was worried about respitory problems - after a lot of work I did manage to get them to change the roof and they decided to put in roof vents ( although on my return I had two head height vents that blow into the horses face ) I have and am still awaiting Perspex windows so I can adjust the wind that blows in - I was promised that walls would be washed down to get rid of the mould - they did them send me the money to replace the bottom boards that were so mouldy but I have had to put boarding to the top to hide the awful mould ( of which they will not contribute ) a true story of poor customer service after the money is in the bank - a year old stable that looks worse than my 9 year old ones - the other one fitted at the time looks like new !!!! Such a shame as I wanted more stables to match but the poor customer service has left a bad taste in my mouth 😢